wacky (adj.)
"疯狂的，古怪的"，1935年，是 whacky（n.）的变体，指"傻瓜"，晚期19世纪的英国俚语，可能最终源于 whack "一击，打击"，因为被打在头上太多次而产生的概念。
wacky 的相关词汇
"to strike sharply," 1719, probably of imitative origin. The noun is from 1737. The word in out of whack (1885) is perhaps the slang meaning "share, just portion" (1785), which may be from the notion of the blow that divides, or the rap of the auctioneer's hammer. To have (or take) a whack at something "make an attempt" is by 1820 (with have), 1845 (with take). Wack or whack "crazy person," 1938, is probably a back-formation from wacky, which probably comes from the blow-on-the-head verb. Related: Whacked; whacking. Whacked out is from 1969.
Wack, whack in the slang sense of "unappealing; crazy," hence "worthless, stupid" is by 1986, apparently popularized by an anti-drug slogan crack is wack.
"疯子"，1938年，由 wacky 反构成。作为俚语形容词的意思是“毫无价值的，愚蠢的”，可追溯到20世纪90年代末。