If something's terrible or bad or boring or just generally negative, it's 'waning'. Derived from the cycles of the moon. Opposite of waxing
I hate having to eat brussel sprouts at xmas, they're waning!
by SpazOnTheHorizon January 06, 2012
1 more definition
The act of pleasuring people of considerable age difference to yourself
e.g, I'm gonna go down to the bingo hall tonight and pick up some old ladies: take em for a bit of waning
by chaotica March 22, 2006