Green’s Dictionary of Slang

cramp n.

[? image of one suffering badly from menstrual cramps]

(US black) an unpleasant, unpopular person.

[US]G. & S. Lorimer Stag Line 68: I thought he was a terrible cramp on account of him being so dumb.
[UK]J. Mowry Way Past Cool 32: Stupid cramp, man! She just like I be tellin you, be workin in there time she forty.