SGROG, 117, a contemptuous name for an old hulk of a woman. 257, an old withered hag. Sgrog caillich. Also an old hat. VI 69, an old hag. [O.N. Skrokkr, body, carcase.]
[SGROG], (MS SGNOG), 201, to pull one’s headdress down tightly on the head.
Dwelly has a whole list of sgrog-related terms, almost all of them referring to a hat, including the act of putting it on, or something shrivelled or shrivelling. He gives sgrogag for little old woman. A sgrogan is a little man.
The term seems to be pretty gender-fluid in general. One play written in the 1830s in the periodical An Teachdaire Ùr Gàidhealach includes the line, “seann sgrog bodaich” (an old sgrog of a man).