gang-rape vs rape

gang-rape is not a noun while rape is a noun.

Word	Noun	Adjective	Verb	Adverb
gang-rape	No	No	Yes	No
rape	Yes	No	Yes	No

As verbs, rape is a hypernym of gang-rape; that is, rape is a word with a broader meaning than gang-rape:

Other hypernyms of gang-rape include assault, dishonor, dishonour, outrage, ravish, violate.

gang-rape (noun)	rape (noun)
	the crime of forcing a person to submit to sexual intercourse against his or her will
	the act of despoiling a country in warfare
	Eurasian plant cultivated for its seed and as a forage crop

gang-rape (verb)	rape (verb)
rape (someone) successively with several attackers	destroy and strip of its possession
	force (someone) to have sex against their will