Word Origin & History
bully (n.)
1538, originally "sweetheart," applied to either sex, from Du. boel "lover, brother," probably dim. of M.H.G. buole "brother," of uncertain origin (cf. Ger. buhle "lover"). Meaning deteriorated 17c. through "fine fellow," "blusterer," to "harasser of the weak" (1653). Perhaps this was by infl. of bull, but a connecting sense between "lover" and "ruffian" may be in "protector of a prostitute," which was one sense of bully (though not specifically attested until 1706). The verb is first attested 1710. The expression meaning "worthy, jolly, admirable" (esp. in 1864 U.S. slang bully for you!) is first attested 1681, and preserves an earlier, positive sense of the word.
[boo
l-ee] 
noun, plural -lies, verb, -lied, -ly⋅ing, adjective, interjection 
