Buck’

n. 1 male deer, hare, rabbit, etc. 2 archaic dandy. 3 (attrib.) slang male. v. 1 (of a horse) jump upwards with its back arched. 2 (usu. foil. by off) throw (a rider) in this way. 3 (usu. foil. by up) colloq. a cheer up. b hurry up; make an effort. [Old English]