Green’s Dictionary of Slang

(US) a Lithuanian.

1971		J. Sharkey in P. Heller In This Corner 158: They called me the ‘Lispin’ Lith’...But it didn’t bother me as long as I got the old paycheck.
1995		in DARE III 373/1: Lit is a fairly common term for a Lithuanian in the Chicago area. It’s neutral when used by people of Lithuanian descent, but mildy derogatory when used by outsiders.