bully vs aggressor

bully and aggressor both are nouns.

Word	Noun	Adjective	Verb	Adverb
bully	Yes	Yes	Yes	No
aggressor	Yes	No	No	No

As nouns, aggressor is a hypernym of bully; that is, aggressor is a word with a broader meaning than bully:

Other hypernyms of bully include assailant, assaulter, attacker.

bully (noun)	aggressor (noun)
a cruel and brutal fellow	someone who attacks
a hired thug	a confident assertive person who acts as instigator

bully (adjective)	aggressor (adjective)
excellent

bully (verb)	aggressor (verb)
discourage or frighten with threats or a domineering manner; intimidate
be bossy towards