fish mousse vs mousse

fish mousse and mousse both are nouns.

Word	Noun	Adjective	Verb	Adverb
fish mousse	Yes	No	No	No
mousse	Yes	No	Yes	No

As nouns, mousse is a hypernym of fish mousse; that is, mousse is a word with a broader meaning than fish mousse:

fish mousse (noun)	mousse (noun)
mousse made with fish	toiletry consisting of an aerosol foam used in hair styling
	a light creamy dish made from fish or meat and set with gelatin
	a rich, frothy, creamy dessert made with whipped egg whites and heavy cream

fish mousse (verb)	mousse (verb)
	apply a styling gel to