busk (v.)
"to prepare, to dress oneself," also "to go, set out," c.1300, probably from Old Norse buask "to prepare oneself," reflexive of bua "to prepare" (see bound (adj.2)) + contraction of Old Norse reflexive pronoun sik. Most common in northern Middle English and surviving chiefly in Scottish and northern English dialect. Related boun had the same senses in northern and Scottish Middle English. Related: Busked; busking.

The nautical term is attested from 1660s (in a general sense of "to tack, to beat to windward"), apparently from obsolete French busquer "to shift, filch, prowl," which is related to Italian buscare "to filch, prowl," Spanish buscar (from Old Spanish boscar), perhaps originally from bosco "wood" (see bush (n.)), with a hunting notion of "beating a wood" to flush game.