köken: From Middle Dutch gheil, from Old Dutch *geil, from Proto-West Germanic *gail, from Proto-Germanic *gailaz, from Proto-Indo-European *gʰoylos (“frothing, tempestuous, wanton”). Cognate to English gole, German geil. The slang meaning of "cool" was likely borrowed from German geil.
köken: Etymology tree Proto-Indo-European *slewbʰ-? Proto-Indo-European *slubʰ-ró- Proto-Italic *slouβr(e/o)kos? Latin lūbricuslbor. Portuguese lúbrico Learned borrowing from Latin lūbricus. Compare lôbrego, probably a doublet.