hothead vs grump

hothead and grump both are nouns.

Word	Noun	Adjective	Verb	Adverb
hothead	Yes	No	No	No
grump	Yes	No	No	No

As nouns, grump is a hypernym of hothead; that is, grump is a word with a broader meaning than hothead:

Other hypernyms of hothead include churl, crank, crosspatch, grouch.

hothead (noun)	grump (noun)
a reckless impetuous irresponsible person	a bad-tempered person
a belligerent grouch