/spruːs/
[adjective] Neat, clean, and well-dressed in appearance. If someone looks spruce, they look tidy and smart, as if they have made an effort with how they present themselves.
Looking 'spruce' originally meant dressed like someone from Prussia — a country famous across medieval Europe for its fine leather goods.
The word 'spruce' carries a hidden geography inside it. To understand it, you have to travel back to the Baltic coast of medieval Europe, to a region known in Old French as 'Pruce' and in medieval Latin as 'Borussia' — the territory we now call Prussia. Medieval traders across northern Europe knew Prussia well, because Prussian merchants supplied some of the finest goods available: timber, amber, and above all, a particular kind of soft, elegant leather used to make fashionable jerkins and jackets.
These leather garments became so popular and so strongly associated with their place of origin that English speakers began calling them 'Spruce leather' — a straightforward anglicisation of 'Pruce', the French name for Prussia. The 'S' crept in at the front through a process linguists call agglutination, where a nearby sound gets absorbed into a word, possibly from phrases like 'of Pruce' being heard and repeated as 'Spruce'. By the 14th century, a 'Spruce jerkin' was a recognisable item of fashionable clothing, the kind of thing a well-heeled young man might wear to impress.
From there, the journey into adjective territory was short and logical. If a Spruce jerkin was an elegant, well-made thing, then a man wearing one looked neat and fine. By the late 16th century, 'spruce' had detached itself entirely from leather goods and was being used freely to describe any person or thing that appeared trim, smart, and carefully turned out. Shakespeare's contemporaries used it with a slight edge — 'spruce' could sometimes suggest someone who was trying a little too hard, a person overly concerned with appearances.
The verb form followed naturally. To 'spruce up' — meaning to make oneself or something else neater and more attractive — arrived in the 17th century and has remained robustly in everyday English ever since. When you tell someone to 'spruce themselves up' before a job interview, you are, without knowing it, sending them off to dress like a medieval Prussian merchant.
Interestingly, the spruce tree — that tall, pointed conifer familiar from Christmas cards and northern forests — shares the same Prussian root. The tree was known as the 'Spruce fir', meaning the fir tree from Prussia, because large quantities of spruce timber were imported to England from Baltic ports. Over time, 'Spruce fir' was shortened simply to 'spruce', and the tree and the adjective went their separate ways in English, few speakers suspecting that both carry the same forgotten Baltic homeland inside them.