"Nifty Fifties"???! Are they serious? The people I know in their 50s are all at the top of their careers, energetic, switched on, fab social lives etc.
I'm genuinely amazed at that
I guess it's one of those things where they come up with a catchy name and then build an excuse to use it around that.
Nothing much positive rhymes with thirties (except maybe 'flirty'), but 'dirty' is the obvious one and not particularly enticing!
For forties? 'Naughty' could attract entirely the wrong audience, who don't realise it's an innocent club and might assume it's for sex people (Lynn).
For sixties? Nothing, really, other than sort of 'pixies', which isn't an adjective anyway.
Seventies? The closest is 'heavenly', which (as well as sounding rubbish) does sort of suggest that you might be already dead or not far off!
Let them have 'nifty fifties' without too much grumbling - it's pretty much all they've got 