Etymology Back-formation from wacky. Alternatively, possibly a blend of white + black, in the sense that it may appear black on the outside, but it's really white on the inside. Compare oreo.
1
Slang Annoyingly or disappointingly bad, in various senses; lousy, corny, cringy, uncool, messed up.
Every record they ever made was straight-up wack.
Ya'll are so wack.2003 September 15, Michael Chapman; Matthew Chapman, “Teen Girl Squad Issue #4”, in Homestar Runner, spoken by Strong Bad as Cheerleader (Matthew Chapman):
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The next day, Phonte gets in, and I let him hear the song, and he goes, 'This dude is wack, but what’s up with that beat though?' And I said, 'It's ours.'2011 May 20, 9th Wonder (quoted), Jaeki Cho, “9th Wonder Tells All: The Stories Behind His Classic Records”, in Complex, archived from the original on 16 Nov 2022:
When TMZ asked Bieber whether he can listen to The Weeknd’s music, the pop superstar replied, "Hell no I can’t listen to a Weeknd song. That shit's wack."2017 January 23, Colin Stutz, “Justin Bieber Says He Can't Listen to The Weeknd's 'Wack' Music”, in Billboard:
"No, no, no," James said Wednesday (via ESPN). "That's wack. That's wack. Why? You got to earn your spot to be in the postseason. No consolation for finishing last. That's corny. That’s corny. That's wack. To play for what? What are they playing for?"2018 March 21, Des Bieler, “'That's wack': LeBron James doesn't like idea of NBA postseason play-in tournament”, in Washington Post:
"He's so wack for that," Jeffryes said of Prescott. "As a black man you should want to speak out against police brutality and racial injustice. You have a black father. One day you will have black children."2018 September 19, Chauncey Alcorn, “Dak Prescott takes heat from Dallas Nine protester after Cowboys game arrests: "He's so wack"”, in Mic:
Etymology Back-formation from wacky. Alternatively, possibly a blend of white + black, in the sense that it may appear black on the outside, but it's really white on the inside. Compare oreo.
A few well chosen words such as "Let's be having you wack!", works wonders. The dockers know that they've got a Scouse to deal with. I'm not saying that a Southerner couldn't handle the situation, but the job might well take longer.1966, The British Journal of Photography, volume 113, H. Greenwood, page 17:
Leading Seaman Hanlon, a tough young man from the Liverpool docks, greeted him with, 'Wot's up with you, wack? Lost yer bleeding maor summat?'2011, Douglas Reeman, Torpedo Run, Random House, →ISBN:
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One of the young men stepped forward to explain. It was obviously an enthusiasm of his. 'Hey, Wack, gerron wiv it, eh?'2019, Richard Woodman, Voyage East, Canelo, →ISBN: