meat grinder vs aggression

meat grinder and aggression both are nouns.

Word	Noun	Adjective	Verb	Adverb
meat grinder	Yes	No	No	No
aggression	Yes	No	No	No

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

Other hypernyms of meat grinder include hostility.

meat grinder (noun)	aggression (noun)
any action resulting in injury or destruction	violent action that is hostile and usually unprovoked
a mill for grinding meat	deliberately unfriendly behavior
	the act of initiating hostilities
	a disposition to behave aggressively
	a feeling of hostility that arouses thoughts of attack