An Etymological Dictionary of the German Language/Schleim
Schleim, m., ‘slime, mucus, phlegm, filth,’ from MidHG. slîm, m., ‘slime, mire, sticky fluid’; OHG. *slîm is wanting. Comp. Du. slijm, ‘slime,’ AS. slîm, and the equiv. E. slime, OIc. slîm, n.; Goth. *sleims is wanting. The root slī̆, ‘to be smooth, slippery,’ contained in these words, which is especially apparent in OHG. slîmen, ‘to male smooth, brighten by grinding,’ is closely related to Lat. lîmare, ‘to file, polish, smooth,’ lîma, ‘file,’ with which probably Lat. lêvis and Gr. λεῖος, ‘smooth,’ are also connected. In Lat. and Gr. initial s disappears before l. Perhaps Lat. lîmus, ‘slime’ (see under Lehm), may be adduced here; comp. further Schleie.