tomcat vs domestic cat

tomcat and domestic cat both are nouns.

Word	Noun	Adjective	Verb	Adverb
tomcat	Yes	No	No	No
domestic cat	Yes	No	No	No

As nouns, domestic cat is a hypernym of tomcat; that is, domestic cat is a word with a broader meaning than tomcat:

Other hypernyms of tomcat include Felis catus, Felis domesticus, house cat.

tomcat (noun)	domestic cat (noun)
male cat	any domesticated member of the genus Felis