Bruin (n.)

Proto-Indo-European root meaning "bright; brown" (the sense connection might involve polished wooden objects).

It forms all or part of: Barnard; bear (n.) "large carnivorous or omnivorous mammal of the family Ursidae;" beaver (n.1) "large amphibious quadruped rodent of the genus Castor;" berserk; brown; Bruin; brunet; brunette; burnish.

It is the hypothetical source of/evidence for its existence is provided by: Old English brun "dark, dusky;" Lithuanian bėras "brown;" Greek phrynos "toad," literally "the brown animal."

"large carnivorous or omnivorous mammal of the family Ursidae," Old English bera "a bear," from Proto-Germanic *bero, literally "the brown (one)" (source also of Old Norse björn, Middle Dutch bere, Dutch beer, Old High German bero, German Bär), usually said to be from PIE root *bher- (2) "bright; brown." There was perhaps a PIE *bheros "dark animal" (compare beaver (n.1) and Greek phrynos "toad," literally "the brown animal").

Greek arktos and Latin ursus retain the PIE root word for "bear" (*rtko; see arctic), but it is believed to have been ritually replaced in the northern branches because of hunters' taboo on names of wild animals (compare the Irish equivalent "the good calf," Welsh "honey-pig," Lithuanian "the licker," Russian medved "honey-eater"). Others connect the Germanic word with Latin ferus "wild," as if it meant "the wild animal (par excellence) of the northern woods."

Used of rude, gruff, uncouth men since 1570s. Symbolic of Russia since 1794.  The stock market meaning "speculator for a fall" is by 1709, a shortening of bearskin jobber (from the proverb sell the bearskin before one has caught the bear); i.e. "one who sells stock for future delivery, expecting that meanwhile prices will fall." Paired with bull from c. 1720. Bear claw as a type of large pastry is from 1942, originally chiefly western U.S. Bear-garden (1590s) was a place where bears were kept for the amusement of spectators.