gel vs hair gel

gel and hair gel both are nouns.

Word	Noun	Adjective	Verb	Adverb
gel	Yes	No	Yes	No
hair gel	Yes	No	No	No

As nouns, gel and hair gel are synonyms defined as:

gel (noun)	hair gel (noun)
a thin translucent membrane used over stage lights for color effects	jellylike substance used in hair styling
jellylike substance used in hair styling
a colloid in a more solid form than a sol

gel (verb)	hair gel (verb)
apply a styling gel to
become a gel