Green’s Dictionary of Slang

t.l. n.

[abbr. Yid. toches lecher, arse-licker]

(US) a toady, a sycophant.

[US]R.A. Wilson Playboy’s Book of Forbidden Words.
[US]Maledicta 1 (Summer) 16: Naturally, he is also a sycophant and toady to the boss: [...] He [...] is a T.L. (tokus-leker: Yiddish), and the boss’s automatic tongue-wiper.