Wacky means amusingly odd. A wacky idea, wacky humour, wacky and cheerful.
It is light and affectionate, and it is the word advertising reaches for when it wants to seem fun, which has worn it out. Wacky belongs to harmless oddity, which is what separates it from any of the words about mental illness.
1adjectivewackyAmusingly odd.
“My aunt has some wacky ideas, like painting her car pink with yellow spots.”
wacky is a quality.
Also accepted in games: quirky
From whack + -y.
Etymology from Wiktionary, CC BY-SA