A "harasser" is someone "who makes others feel uncomfortable [by] using words", gestures, and touch.
A "stalker" is someone "who makes others feel uncomfortable" by persistently trying to interact with them, either by using information they thought was private, and/or after they had told the stalker to have no further contact with them.
As Arrowfar suggested, "lowlife" is an offensive term for a poor person who might have criminal intentions.
"Crook" is a mildly offensive term for a criminal. For example, when Richard Nixon said, "I am not a crook", it immediately made many people think he was a "lowlife" and unworthy of being President.
"Mugger" is a factual (but still insulting) term for a criminal who robs people on the street or in alleys by force (or threat of force).
"Thug" is an offensive term for an intimidating, possibly criminal, person. Many bodyguards and muggers are called thugs.
"Rapist" and "child molester" are factual terms for people who commit particular crimes. Because these crimes are so abhorrent (especially to many imprisoned criminals), they are very insulting terms. (Many criminals consider it honorable to harm or kill rapists and child molesters.)
In the UK, posh is used primarily by working class people. It is used by aspirational ones in a positive way, "we got dressed up all posh, like", but it can also have a derogatory meaning. If you offered a napkin to a proud-to-be-working-class man, he might reply
Naa, I'm not posh, mate.
ladida is a mild expression of disapproval of somebody's affectations.
poncy is a working class way of saying "pretentious", and it's definitely derogatory. This might be used about the shirt:
You won't catch me wearing a poncy shirt like that!
Best Answer
The word you may be looking for is snob.
Someone who is a snob, thinks they are better than others (whether or not they actually are) and can be based on class divisions.
There are intellectual snobs, social snobs, economic snobs, the list goes on...
Another possible word is elitist.
but tends to be more class related.
A phrase which gets used to separate those who worship profits at any cost is
and refers to persons who look to enrich themselves at the expense of the (relatively) less advantaged, they usually have a disdain (or no time) for those with less money than themselves. Think The Great Gatsby or The Wolf of Wall Street. Capitalists, especially Darwinian Capitalists, will tend to believe that their success is due to superiority in ability and those with less are of a lesser ability. This should not be confused with the Calvinist belief that earthly success is a sign of God's grace.