ill will vs aggression

ill will and aggression both are nouns.

Word	Noun	Adjective	Verb	Adverb
ill will	Yes	No	No	No
aggression	Yes	No	No	No

As nouns, aggression is a hyponym of ill will; that is, aggression is a word with a more specific, narrower meaning than ill will:

ill will (noun)	aggression (noun)
a hostile (very unfriendly) disposition	violent action that is hostile and usually unprovoked
the feeling of a hostile person	deliberately unfriendly behavior
	the act of initiating hostilities
	a disposition to behave aggressively
	a feeling of hostility that arouses thoughts of attack