When a slang word catches on, students of language often have a difficult time figuring out its meanings and origin. This, I suspect, is because it emerges not like Athene—a fully formed adult released from the mind of Zeus—but like several thousand frog eggs—similar in appearance to one another but bewildering in number and neither well defined nor mature.
Eventually usage of a slang term X will probably coalesce around one or a few more-or-less clearly understood meanings, but in the meantime the only reasonable way to answer questions such as “what does X mean?” is to identify as many of the ways in which the word is being used as you can.
Without attempting to be exhaustive, I took my frog egg search to the least professional-looking authority I could easily find—which turned out to be Caitlin Corsetti’s “Define That: Ratchet” blog post at Gurl.com—and then consulted not Ms. Corsetti but the commenters responding to her post. From them I learned the following things about ratchet.
What does 'ratchet' mean, and how is it pronounced?
Ratchet [is] used to describe someone means nasty, ghetto or trifling. —Janet
Ratchet also means a situation or process that is perceived to be deteriorating or changing steadily in a series of irreversible steps. It is used as a term for something low class or deteriorated. Similar to how we use the term ghetto. —NyxoftheNight
Ratchet means: ghetto, stupid, rediculous, cheap —selena
I have heard my teen-aged granddaughter use this word in reference to her own hair, and she was completely unable to define it or explain what she meant by it. All she could say was, You know, grandma, it’s just rachet! —cat
It’s just simply a mispronunciation of “wretched”. The same people that use it often describe a “ratchet girl” [as] someone that wears torn “stalkings”. —JBW
It is a pure homonym that has nothing to do with a ratchet wrench, or “wretched.” It means RAT SHIT. —Becky
The first time I asked someone for a definition for this slang, I was told it meant “A woman who’s only good for one thing — getting a nut off … like a ratchet.” —Scott Simpson
its not ratchet that people say its ratchid is what they say! two different words —lollipop
Racheted is what I keep hearing [people say] —acer
Where does it come from, when was it first used, and who or what popularized it?
It originated in the 17th century and is a lesser used meaning of the word that has evolved into a more contemporary meaning. —James
Ratchets been around since the XVIII c. annoying people with their terrible racket, so less fortunate husbands soon started to call it to their ghastly wives —moi même
It is a derivation of the two words “rat” and “shit” as in the situation is, person is, place is so bad it is as bad or worse than “rat shit.” Totally trash talk. —Lily Bear
I think its after nurse Ratched from one flew [over] the cuckoos nest. —carlsjr
The term came from Cedar Grove [in] the City of Shreveport Alabama. Popularized by the song, “Do Tha Ratchet” True origin was spun out of slurring the word WRETCHED Now has become a massively overused typo. —Matt
watch emanuel & philip hudsons she ratchet video —selena
Is it a "good"/positive word, or "bad"/negative, and has this changed in any way?
The current slang use of this word has a very nasty, biting undertone to it. The other comments in this thread alone support the connotations of being undesirable. —cat
About 20yrs ago I somehow caught a nickname (ratchet) due to my ability to fix or repair nearly anything. I understood It’s relation to my daily work and eventually I got used to it. I was told by a college girl I should never be ratchet, it completely through me off and I was simply looking at this girl as if she was crazy. —Adam Draughn
The experts above have spoken pretty clearly about what ratchet means, where it came from, and so on. I would only add that Emmanuel N Phillip Hudson uploaded their “Ratchet Girl Anthem” (cited by selena above) to YouTube twice (on January 16, 2012, and April 26, 2012) and that the two versions have accumulated a combined 56.1 million views. With regard to the mystery of the sudden popularity of ratchet, I think we may have a couple of major suspects (if not the actual perpetrators) here.
Lava House and Lil' Boosie's "Do tha Ratchet" (cited by Matt above) deserves some attention because it is considerably older than "Ratchet Girl Anthem." According to LyricWikia, it was released in 2006. The most frequently watched YouTube video for this song was posted on July 26, 2009, and has garnered an impressive 793,000 views despite being a static image accompanied by Lil' Boosie's audio track; still, 793,000 isn't 56.1 million.
As to whether ratchet is meant to be generally understood in a positive or a negative sense, that aspect of the term may well be in flux, just as everything else about it appears to be. In Lil' Boosie's world, ratchet is almost an environmental term: It applies to men (including LB himself) and to women, and it describes most of their doings in the neighborhood where he lives. In contrast, the Hudsons use ratchet specifically in connection with women and do not indicate any sympathy for anyone so described.
Speaking as a complete outsider, with no prior knowledge of ratchet as post–Jimmy Cliff slang, I have to say that the term as used by the Hudsons reminds me quite a bit of skanky, which derived from skank (“An unattractive woman; a malodorous woman; =SKAG,” according to Robert Chapman and Barbara Kipfer, Dictionary of American Slang, third edition [1995]). Here is the Chapman & Kipfer entry for skanky:
skanky or skank-o-rama adj 1980s teenagers fr black Nasty; repellant; =GROTTY, SCUZZY, TRASHY: The girls were somewhat skanky, with lank hair and rotten posture—Richard Price/ ...you moved, the earth moved. Skank-o-rama—Sassy
Both skanky and ratchet (as used in the Hudsons’ comical YouTube video, anyway) are not gender-neutral terms, though none of the Gurl.com experts expressly makes this point about ratchet.
It will be interesting to see whether the gender connection that "Ratchet Girl Anthem" promotes influences the long-term sense of the word, notwithstanding Lil' Boosie's earlier, more broadly applicable sense of the term. The crucial factor here, probably, is the proportion of users who base their knowledge of the term on the Hudsons' song versus the proportion of those who adopted the term as it was used in the older Shreveport, Louisiana, tradition.
Best Answer
The second definition in JoeBright's answer is correct: thot is an acronym that stands for "That Ho Over There." The word has a negative connotation and is such sometimes used as an affectionate insult to close friends, but is almost always used to describe women. Ho is commonly misspelled as hoe, but intended as a short form for whore. It's generally considered AAVE, with multiple examples in hip-hop culture.
Unlike in the case of YOLO, where Drake's song "The Motto" popularised it, there seems to be no single event. Rather, the word rose to popularity gradually.
This is going to be long...
I did find a song called "Thot Walk," performed by artists John Boy, Kayleb, and Yung Cyph, but it was made after thot reached its peak popularity on Twitter. (It did start a trend on Vine, but that's another story.)
Examples of characteristics the song states are typically attributed to a thot: (couldn't find lyrics, all by ear):
So desperate for attention is this thot that she dresses as provocatively as possible to attract as many Likes as possible, most of which come from heterosexual men (for reasons which should be obvious).
She has a body considered by society to be physically attractive (large breasts & butt, most likely) yet her face is unattractive. This may be because she has an awkward bone structure, is unkempt with her appearance, or is unskilled at applying makeup in a flattering fashion.
It's common on Vine for users to share videos of themselves or others twerking. Since some can even experience their 15 minutes of viral video fame as a result of a twerk Vine, the phrase do it for the Vine has leverage in persuading someone to do anything they wouldn't normally do (not just twerking) for the sake of humour or interest. I believe, however, that Kayleb is using the phrase with thinly-veiled condescension, thinking of girls who twerk for Vines as gullible or attention-seeking.
Those in the VIP section of a club are there most likely either because they have money, fame, or connections to someone associated with the club. John Boy implies that having sexual relations with the promoter is a cheap or dishonest way of getting in.
Once under the influence of alcohol, a thot will become promiscuous (or exchange sexual services for money, I wasn't sure).
Along with the concrete examples of thot behaviour, these two lines may also be of interest.
These two phrases, both without followup, suggest that there is more to being a thot than just simply being promiscuous. Part of being a thot has to do with how one carries oneself - perhaps speech patterns, lexicon, gait, posture, and/or body language are all variables in determining whether someone is a thot.
I've also searched up the word on Twitter to see how it'd be used in context, and while I did see a few instances of it being used as a shortening of thought as GEdgar suggested, those were well in the minority.
It is illogical to discard a diamond and replace it with a rock because of the drop in value: by analogy, a thot has much lower value than a wife.
Birds of a feather flock together.
Thot was clearly being used as an untrue allegation to save face publicly.
Also provides evidence to suggest that a thot carries herself differently. Presumably, a woman who "runs game" could very well also be promiscuous, but carries herself in such a way that earns her respect, reverence, or unrequited love.
I can assume from this tweet that the scenario in which a girl previously perceived as beautiful becomes a thot is common. The user laments because he believes becoming a thot is shameful.
An exception to the rule: Previously used only by men toward women, this is a woman not wanting to associate herself with anything having to do with thots.
As previously stated, a thot is most definitely promiscuous, but considering the evidence, one can start to form a profile.
A thot is well-connected on social media, but most likely has received most of her attention from desperate heterosexual men hoping to get an easy lay. Unattractive with a sense of grandeur, or perhaps attractive only with makeup, she barely only looks good enough to attract this attention. She is shameless, dishonest, or not self-aware, with further personal boundaries than most. There are a wide variety of men with whom she is willing to sustain a sexual relationship, reoccuring or not. She twerks, or does any other activity notorious for being a blatantly sexual way of attracting attention. She is a common enough occurrence for her value to have diminished. Her behaviour would be unsuitable in polite company. She befriends other thots, while other women who see themselves as better do not wish to associate with her.
Also, that ho over there is a phrase that puts physical distance between the narrator and the ho. Extrapolating, it could imply disinterest or detachment, as if the narrator knows there will be another ho over there, and over there, and over there.
And that's a thot.
The social implications of the word and its usage are a whole other can of worms, and out of the scope of this site.