assault vs gang-rape

assault is a noun but gang-rape is not a noun.

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

As verbs, gang-rape is a hyponym of assault; that is, gang-rape is a word with a more specific, narrower meaning than assault:

assault (noun)	gang-rape (noun)
close fighting during the culmination of a military attack
a threatened or attempted physical attack by someone who appears to be able to cause bodily harm if not stopped
the crime of forcing a person to submit to sexual intercourse against his or her will

assault (verb)	gang-rape (verb)
attack in speech or writing	rape (someone) successively with several attackers
attack someone physically or emotionally
force (someone) to have sex against their will