grump vs crab

grump and crab both are nouns.

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

As nouns, crab is a hyponym of grump; that is, crab is a word with a more specific, narrower meaning than grump:

Other hyponyms of grump include crabby person, fire-eater, hothead, misanthrope, misanthropist.

grump (noun)	crab (noun)
a bad-tempered person	a stroke of the oar that either misses the water or digs too deeply
	decapod having eyes on short stalks and a broad flattened carapace with a small abdomen folded under the thorax and pincers
	a louse that infests the pubic region of the human body
	the edible flesh of any of various crabs
	a quarrelsome grouch

grump (verb)	crab (verb)
	complain
	fish for crab
	scurry sideways like a crab
	direct (an aircraft) into a crosswind