exclusion vs rejection

exclusion and rejection both are nouns.

Word	Noun	Adjective	Verb	Adverb
exclusion	Yes	No	No	No
rejection	Yes	No	No	No

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

exclusion (noun)	rejection (noun)
the act of forcing out someone or something	the act of rejecting something
a deliberate act of omission	the speech act of rejecting
the state of being excluded	(medicine) an immunological response that refuses to accept substances or organisms that are recognized as foreign
the state of being excommunicated	the state of being rejected