Meaning – ‘Pussy(cat)’ vs ‘Cat’ Comparison

There is no relation between a woman's genitals and a coward. The meaning of "coward" comes from something else.

Many people think that "pussy" is an diminutive of pusillanimous

pusillanimous

showing a lack of courage or determination; timid.

but a wikipedia article suggests that "pussy" is used as an alternate spelling of an obsolete English word "pursy".

The word pussy can also be used in a derogatory sense to refer to a male who is not considered sufficiently masculine (see Gender role). When used in this sense, it carries the implication of being easily fatigued, weak or cowardly.

According to OED, pussy actually comes from the word puss, a well-used name for cats at that time. It was first used to mean cat.

"cat," 1726, diminutive of puss (n.1), also used of a rabbit (1715). As a term of endearment for a girl or woman, from 1580s (also used of effeminate men). Pussy willow is from 1869, on notion of "soft and furry." To play pussy was World War II RAF slang for "to take advantage of cloud cover, jumping from cloud to cloud to shadow a potential victim or avoid recognition."

Later in the 19th century, it was used as a slang for "female pudenda"

slang for "female pudenda," 1879, but probably older; perhaps from Old Norse puss "pocket, pouch" (cf. Low German puse "vulva"), but perhaps instead from the cat word (see pussy (n.1)) on notion of "soft, warm, furry thing;" cf. French le chat, which also has a double meaning, feline and genital. Earlier uses are difficult to distinguish from pussy (n.1), e.g.: The word pussie is now used of a woman [Philip Stubbes, "The Anatomie of Abuses," 1583] But the use of pussy as a term of endearment argues against the vaginal sense being generally known before late 19c., e.g.: "What do you think, pussy?" said her father to Eva. [Harriet Beecher Stowe, "Uncle Tom's Cabin," 1852] Pussy-whipped first attested 1956.

According to etymonline.com, the word pussy is a diminutive of the word puss, which means cat, and which was also used as both an insult and, subsequently, a term of endearment for women (emphasis mine):

puss (n.1)

 "cat," 1520s, but probably much older than the record, perhaps imitative of the hissing sound commonly used to get a cat's attention. A conventional name for a cat in Germanic languages and as far off as Afghanistan; it is the root of the principal word for "cat" in Rumanian (pisica) and secondary words in Lithuanian (puz), Low German (puus), Swedish dialect katte-pus, etc. Applied to a girl or woman from c. 1600, originally in a negative sense, implying unpleasant cat-like qualities; but by mid-19c. in affectionate use.

Puss gave rise to pussy which was used in the same basic way:

pussy (n.1)

"cat," 1726, diminutive of puss (n.1), also used of a rabbit (1715). As a term of endearment for a girl or woman, from 1580s (also used of effeminate men). To play pussy was World War II RAF slang for "to take advantage of cloud cover, jumping from cloud to cloud to shadow a potential victim or avoid recognition."

I remember being quite shocked as an adolescent when, while reading an Agatha Christie novel, I came across as description of a kindly old lady as "a nice old pussy" (the quote below may or may not be the one I remember, I found it in what seems to be a collected edition entitled "A Caribbean Mystery ; A Pocket Full of Rye ; The Mirror Crack'd from Side to Side ; They Do it with Mirrors available in Google Books):

I also found the following in The Detective Novels of Agatha Christie: A Reader's Guide by James Zemboy:

"A Nice Old Pussy" who lives with Ann Shapland's mother and copes most of the time.

And, in the same book, an explanation of the usage for modern readers:

I found few other examples. I'm sure there are more but, as you can imagine, my search was confounded by the other, more vulgar meaning of the word. This one is from The Life and Letters of the Right Honourable Friedrich Max Muller, Volume 1, and seems to be used to describe the author's daughter, of all people:

So yes, the word was indeed used as a form of endearment, at least as recently as the first half of the previous century. However, I strongly advise you not to use the word as a term of endearment. You will very likely be misunderstood unless the context is very clear.

Finally, while I have spent 4 years living in the UK, that was more than a decade ago and I can't claim to be an expert on BrE. Nevertheless, I will attest to never having heard the term used as a form of endearment for non-felines there and I would be very surprised to learn that said usage is still common.