Webster's Revised Unabridged Dictionary · 1913

Shag

Shag , noun

[Anglo-Saxon sceacga a bush of hair; akin to Icelandic skegg the beard, Swedish skagg, Danish skj{not transcribed}g. Compare Schock of hair.]

1.
Coarse hair or nap; rough, woolly hair.
True Witney broadcloth, with its shag unshorn. — Gay
2.
A kind of cloth having a long, coarse nap.
3.
(Commerce) A kind of prepared tobacco cut fine.
4.
(Zoology) Any species of cormorant.

Shag , adjective

Hairy; shaggy. — Shakespeare

Shag , transitive verb

To make hairy or shaggy; hence, to make rough.
Shag the green zone that bounds the boreal skies. — J. Barlow