seen!, excl. — Green’s Dictionary of Slang

seen! excl.

[although the term is used as a synon. for SE yes, the implication is one of bearing witness and thus of a more profound agreement with the speaker]

(orig. W.I.)

1. (also sceen!) a general excl. of affirmation.

1980		(con. 1950s) M. Thelwell Harder They Come 128: ‘Cool yourself, young bwai, you in business.’ ‘Sceen, man.’.
1997		N. Barlay Curvy Lovebox 29: Yeah man seen na mean.
2001		(con. 1981) A. Wheatle East of Acre Lane 177: ‘Too many crub-hungry yout’s around.’ ‘Seen,’ Yardman laughed.
2020		G. Krauze What They Was 116: Gotti says he’s a dickhead really [...] and I say seen.

2. a general excl., ‘do you understand?’.

1984		Smiley Culture ‘Cockney Translation’ 🎵 Sweet as a nut – just level vibes. Seen?
1992		V. Headley Yardie 136: Call a lawyer fe me, seen?
2001		K. Sampson Outlaws (ms.) 41: Don’t want you letting the man in no more, Fonzie. Seen?