rejection vs human activity

rejection and human activity both are nouns.

Word	Noun	Adjective	Verb	Adverb
rejection	Yes	No	No	No
human activity	Yes	No	No	No

As nouns, human activity is a hypernym of rejection; that is, human activity is a word with a broader meaning than rejection:

Other hypernyms of rejection include act, deed, human action.

rejection (noun)	human activity (noun)
the act of rejecting something	something that people do or cause to happen
the speech act of rejecting
(medicine) an immunological response that refuses to accept substances or organisms that are recognized as foreign
the state of being rejected