Brit
wiktionary
From Middle English brytten, brutten, from Old English brittian, bryttian(“to divide, dispense, distribute, rule over, possess, enjoy the use of”), from Proto-Germanic *brutjaną(“to break, divide”), from Proto-Indo-European *bʰrewd-(“to break”). Cognate with Icelandic brytja(“to chop up, break in pieces, slaughter”), Swedish bryta(“to break, fracture, cut off”), Danish bryde(“to break”), and outside the Germanic family with Albanian brydh(“I make crumbly, friable, soft”). Related to Old English brytta(“dispenser, giver, author, governor, prince”), Old English brēotan(“to break in pieces, hew down, demolish, destroy, kill”).
Probably from Middle English bret or birt, applied to a different kind of fish. See bret.
Short for brit milah.
etymonline
Brit (n.)
U.S. colloquial shortening of Britisher or Briton, 1901, formerly (with Britisher) felt as offensive by Englishmen traveling in the States, who regarded it as another instance of the "odious vulgarism" of the Americans, but Bret and Bryt were common Old English words for the (Celtic) Britons and survived until c. 1300. In Old French, Bret as an adjective meant "British, Breton; cunning, crafty; simple-minded, stupid."
