rejection vs speech act

rejection and speech act both are nouns.

Word	Noun	Adjective	Verb	Adverb
rejection	Yes	No	No	No
speech act	Yes	No	No	No

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

rejection (noun)	speech act (noun)
the act of rejecting something	the use of language to perform some act
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