Green’s Dictionary of Slang

(US black) a loss; usu. in phr. take a l.

1998		Big L ‘Ebonics’ 🎵 You took a l, you took a loss.
2017		1011 ‘No Hook’ 🎵 Free Criminal he got birded / That’s a L but I know he'll firm it.
2020		S.A. Crosby Blacktop Wasteland 7: ‘Yo, man, you lost. Just take the L and admit the Olds ain’t as legendary as you thought’.
2022		Digga D. ‘Hold It Down’ 🎵 f I went to jail, took that L, would you tell all your girls / That you still have love for me?