Something that is bad, inferior, or of poor quality; also slang for uncool, crazy, or messed up.
Origin uncertain, possibly from onomatopoeia or shortening of 'whack.' The slang usage became popular in 1980s hip-hop culture to mean 'bad' or 'uncool,' which is the opposite of what 'whack' might suggest.
The funny thing about 'wack' is that it's an invented word that hip-hop popularized—linguistic scholars studied how this one slang term from a subculture became mainstream vocabulary in the 1980s-90s, showing how music shapes language!
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