Webster's Revised Unabridged Dictionary · 1913

Skainsmate

Skainsmate , noun

[Perhaps originally, a companion in winding thread (see Skein), or a companion in arms, from skain a sword (see Skean).]

A messmate; a companion. [Obsolete]
Scurvy knave! I am none of his firt-gills; I am none of his skainsmates. — Shakespeare