From Middle EnglishSpruce, an alteration of Pruce(“Prussia”), from Medieval Latin, from a Baltic language, probably Old Prussian; for more, see Prussia. Spruce, spruse (1412), and Sprws (1378) were terms for commodities brought to England by Hanseatic merchants (beer, wood, leather). The tree with this name was also believed to have been native to Prussia. The adjective and verb senses ("trim, neat" and "to make trim, neat") are attested from 1594, and originate with spruce leather (1466), which was used to make a popular style of jerkins in the 1400s that was considered smart-looking.
This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium. Particularly: “"Spruce leather" because tanned with the tree bark, or only because it came from Prussia? Split into two etymologies?”
1606, William Warner, “The Sixteenth Booke. Chapter CI.”, in A Continuance of Albions England:[…], London:[…] Felix Kyngston [and Richard Bradock?] for George Potter,[…], →OCLC, page 399:
Hovv often vvould the Svvaines prepare their Morrice & their May / To haue a ſight of her, vvhen all enamoured vvent their vvay?/ The ſprevvſeſt Citie-Lads for her vvould faine the Countrie-aire, / And that their prouder Girles had but adultrate beauties ſvvaire, […]
[A] baker's boy in a white apron and blue jumpers went by carrying a basket of bread on his head; and from the nearby tobacconist's, a spruce young lieutenant dressed in a black uniform emerged lighting a cigarette.
He had great neatness of person, and he continued to wear his spruce black coat and his bowler hat, always a little too small for him, in a dapper, jaunty manner.