employ (n.)
1660s, "action of employing," from French emploi, from Middle French verb employer (see employ (v.)). From 1709 as "state of being employed."
employ (v.)
early 15c., "apply or devote (something to some purpose); expend or spend," from Old French emploiier (12c.) "make use of, apply; increase; entangle; devote," from Latin implicare "enfold, involve, be connected with, unite, associate," from assimilated form of in- (from PIE root *en "in") + plicare "to fold" (from PIE root *plek- "to plait").

Imply, which is the same word, retains more of the original sense. Sense of "hire, engage" first recorded in English 1580s, from meaning "involve in a particular purpose," which arose in Late Latin. Related: Employed; employing; employable.