wacky

[ wak-ee ]

/ ˈwæk i /

odd or irrational; crazy: They had some wacky plan for selling more books.

Also whacky.

Origin of wacky

1935–40; apparently whack (noun, as in out of whack) + -y¹

wack·i·ly, adverb wack·i·ness, noun

wace, wack, wacke, wacked-out, wacko, wacky, wacky tobacky, waco, wad, wad medani, wada

wacky

/ (ˈwækɪ) /

slang eccentric, erratic, or unpredictable

wackily, adverb wackiness, noun

C19 (in dialect sense: a fool, an eccentric): from whack (hence, a whacky, a person who behaves as if he had been whacked on the head)