Green’s Dictionary of Slang

(W.I.) unpleasant, uncooperative.

1950		Kingston Gleaner 17 Nov. 🌐 ‘Instead of you believe it is the boy alone going to get sheg, you are going to get sheg too’.
1970s		T. Rhone Gloss. in Old Story Time (1981) n.p.: sheg-up: uncooperative, standoffish.
1995		Francis-Jackson Official Dancehall Dict. 47: Sheg-up 1. a dirty attitude: u. ’im sheg up/he has a nasty attitude.
2016		Star (Jamaica) 22 Feb. 🌐 Just wait till we buss pon di teleprt ting. Dem get sheg! LAMO! Wowie! Next week you peeps take care!