The meaning of "Bully"

A quick scan through the Mighty Oxford reveals some answers to the question people keep on asking me.

WHAT DOES THE WORD 'BULLY' MEAN?

1. A term of endearment and familiarity originally applied to either sex e.g. sweetheart. Later to men only, implying friendly admiration: good friend, fine fellow. Often prefixed as a sort of title to the name of the person addressed as in Shakespeare - bully Bottom. Now obsolete.

2. Brother, companion.

3. A blustery 'gallant' or 'swash-buckler', now esp. a tyrannical coward who makes himself a terror to the weak.

4. The protector of a prostitute, one who lives by protecting prostitutes.

With thanks to Elizabeth Caffin