bullying vs aggression

bullying and aggression both are nouns.

Word	Noun	Adjective	Verb	Adverb
bullying	Yes	Yes	No	No
aggression	Yes	No	No	No

As nouns, aggression is a hypernym of bullying; that is, aggression is a word with a broader meaning than bullying:

bullying (noun)	aggression (noun)
the act of intimidating a weaker person to make them do something	violent action that is hostile and usually unprovoked
	deliberately unfriendly behavior
	the act of initiating hostilities
	a disposition to behave aggressively
	a feeling of hostility that arouses thoughts of attack

bullying (adjective)	aggression (adjective)
noisily domineering; tending to browbeat others