if yk yk Share definition Flag An acronym for the phrase "if you know you know". Often used in text. "Many college students smoke marijuana and become sluggish, lazy, stupid, and unconcerned." "What???" "If yk yk" if yk yk by HotMemeBoi34 April 19, 2021 0 0 Get merch Get the if yk yk mug. Buy Now — $32.95 See more merch