Merriam-Webster's Collegiate® Dictionary, 11th Edition
CRAB
I. noun
Usage: often attributive see: carve Date: before 12th century any of numerous chiefly marine broadly built decapod crustaceans:, any of an infraorder (Brachyura) with a short broad usually flattened carapace, a small abdomen that curls forward beneath the body, short antennae, and the anterior pair of limbs modified as grasping pincers, any of various crustaceans of an infraorder (Anomura) resembling true crabs in the more or less reduced condition of the abdomen, cancer 1, infestation with crab lice, the angular difference between an aircraft's course and the heading necessary to make that course in the presence of a crosswind,
II. verb (crabbed; crabbing)
Date: 1657
intransitive verb to fish for crabs,
2. a. to move sideways indirectly or diagonally, to crab an airplane, to scuttle or scurry sideways, transitive verb to cause to move sideways or in an indirect or diagonal manner, to subject to crabbing, crabber noun
III. noun
Etymology: Middle English crabbe, perhaps from crabbe 1crab
Date: 14th century
crab apple ,
IV. noun
Date: 1580
an ill-tempered person ; grouch ,
V. verb (crabbed; crabbing)
Etymology: Middle English crabben, probably back-formation from crabbed
Date: 1662
transitive verb to make sullen ; sour , to complain about peevishly, spoil , ruin , intransitive verb carp , grouse , crabber noun