An Etymological Dictionary of the German Language/Unschlitt
Unschlitt, Inschlitt (Inselt), n., ‘suet, tallow,’ from MidHG. unslit (unselt), inslit (inselt), n., ‘tallow,’ of which there are abundant variants in MidHG. Comp. OHG. unslit, ‘fat, tallow’ (AS. unslid, or rather unflid, ‘fat, grease, tallow,’ is uncertain). MidHG. unsleht, ‘tallow’ (Rhen.-Franc. inschlicht), seems to be connected with MidHG. (in)geslehte, n., ‘entrails.’ The derivation of the word cannot be more definitely determined, since the older forms are unknown; Hess. and LG. ungel, ‘tallow,’ suggests the supposition that OHG. unslit has originated in *ungslit.