Green’s Dictionary of Slang

(Irish) to look.

1908		L. Doyle Ballygullion (1927) 79: I seen him skellyin’ across, an’ whin I looked, who should I see but Susy.
1913		A. Irvine My Lady of the Chimney Corner 119: It was noised abroad that he had been caught in the act of ‘skellyin’’ at her.
1979		J. Morrow Confessions of Proinsias O’Toole 77: All the way he kept skellying at his watch.