lave

The verb is derived from Middle English laven (“to bathe, wash; to bail or draw water, drain, exhaust; to dampen, wet; to pour; of water, etc.: to flow, stream”), and then partly: from Old French laver (“to be washed; to wash”) (modern French laver (“to wash (oneself)”)), from Latin lavāre, the present active infinitive of lavō (“to bathe, wash; to dampen, wet”), ultimately from Proto-Indo-European lewh₃- (“to wash”); and from Old English lafian (“to bathe; to make wet; to ladle out; to pour”), from Proto-West Germanic labōn (“to refresh, revitalize; to strengthen”); further etymology uncertain, possibly from Latin lavō (see above) but this does not explain the change in meaning from “to wash; to wet” to “to refresh; to strengthen”. Perhaps Old English lafian is derived directly from the Latin word, and Proto-West Germanic *labōn and words in languages derived from it such as Dutch and German are coincidentally similar to the Old English word. The noun is derived from the verb.

From Northern Middle English lave, Middle English love, Early Middle English lafe (“remainder, rest; legacy; relict, widow”), from Old English lāf (“remainder, rest; heirloom; legacy; relict, widow”), from Proto-West Germanic laibu (“remainder”), from Proto-Germanic laibō (“remainder, remnant”), from lībaną (“to be left, to remain”), probably from Proto-Indo-European leyp- (“to stick; fat or sticky substance”). Doublet of belive (“(obsolete except UK, dialectal) to remain, stay”). Cognates * Old English belīfan (“to remain”) * Old High German leiba (“to lave”) * Old Norse leif (“to lave”)

The adjective is from Middle English lave (“of the ears: drooping, hanging down”), from Old Norse lafa, from Proto-Germanic labēn- (“to dangle”), from Proto-Indo-European leb- (“to hang down loosely (?)”). The verb is probably derived from the adjective.