WordNet sense 1 (a quarrelsome grouch):

crabby person

WordNet sense 2 ((astrology) a person who is born while the sun is in Cancer):

cancer

WordNet sense 3 (the fourth sign of the zodiac; the sun is in this sign from about June 21 to July 22):

Cancer the Crab

WordNet sense 4 (the edible flesh of any of various crabs):

crabmeat

WordNet sense 5 (infests the pubic region of the human body):

crab louse, Phthirius pubis, pubic louse

WordNet sense 6 (complain):

beef, bellyache, gripe, grouse, holler, squawk