now I'm curious again about the etymology of various British slang. I know what things like "for a game of soldiers", "you're pulled", and "big girl's blouse" mean, but why do they mean that?

My disctionary of slang is at home, Connie, but my native-user's understanding of these phrases is as follows (other natives, not to mention experts, will doubtless want to disagree in some or all cases, because folk entomology is like that).

"Bugger (or damn, or blow) this for a game of soldiers" means 'give this up because it's pointless', the reference being to a child's game. I think the related phrase "[verb] this for a lark" is probably from lark as a verb, to play around, rather than lark as a noun, a small bird, though either is possible in the context.

"You've pulled" I don't really know the origin of. I guess there might have been a previous useage of 'pulled' to mean 'succeeded', but there might not; almost any word in English means something to do with sex if you want it to. But this review of the new Brewer's Phrase and Fable gives a nice description of its context:

This is part of the lexicon of New Lads, who appeared as the natural constituency of Loaded magazine and its imitators, in which cocky braggadocio took the place of gallantry.

It's almost tempting to link it to 'have the pull on someone', to have power over them.

"Big girl's blouse" is older, and standard sites like World Wide Words agree that its origin is a mystery. I guess it's an over-elaborate (thus teasing and light-hearted) version of the fairly basic man-calling-another-man-a-woman insult, along the lines of 'cunt', 'nancy', etc.

This is how much I'm avoiding reading Locke's Essay on Human Understanding.

This is how much I'm avoiding reading Locke's Essay on Human Understanding

Thank you much, dear. I've always been particularly puzzled by "big girl's blouse" because I tried to analyze and came up with "wrapped around the body of a girl, particularly the bit with the tits--how is that bad?"

You're welcome, Connie. I'm fairly sure it's a "you have the attributes of something feminine" insult-- probably "you're like a girl's blouse" (frilly and lightweight?) comes first. Though your rendering does make grammatical sense.

"big girl's blouse"

It's not a rhyming slang thang?

I'm fairly sure it's not rhyming slang. For one thing, while it might be used anywhere in England now, I think it's a Northerner's phrase originally, rather than Cockney. For another, I've a fair bit of rhyming slang (my great-grandfather is reputed to have spoken it natively and the family is fond of dropping it into conversation) and I've never met it in that context.

ETA: and the use of 'big' at the start of the phrase would be atypical.

OK, so explain "go all pear-shaped" ??

Also, a co-worker just reminded me of the Brit slang "poofter" and I'm wondering if it's from the Greek "pufti" (homosexual, derogatory) or if the etymology is the other way round.

On the basis of nothin', I'm thinking that it's the other way round. I can remember Monty Python using "poofter" in the late 60s, so the usage could have spread that way.

'Go all pear-shaped' is a mystery to me, Raq. I've heard a couple of explanations so unconvicing that I've forgotten them, and that's all. I guess it's a case where folk entomology goes all pear-shaped.

Amchau, how's it going? Are you enjoying school? I can't recall, are you at Nottingham, or am I misremembering?

ISTR that "go all pear-shaped" came from tedious penmanship lessons, when eventual fatique and boredom made the practice "O"s turn out pear-shaped instead of circular.