"one who accepts and pays off bets at agreed-upon odds," 1885, a colloquial shortening of bookmaker in the wagering sense.
Entries linking to bookie
bookmaker n.
also book-maker, 1510s, "printer and binder of books," from book (n.) + agent noun from make (v.). The wagering sense of "professional bettor, one who takes bets on horse races, etc., calculates odds, and pays out winnings" is from 1862. Related: Book-making (late 15c., betting sense 1824).