exert (v.) Look up exert at Dictionary.com
1660s, "thrust forth, push out," from Latin exertus/exsertus, past participle of exerere/exserere "thrust out, put forth," from ex- "out" (see ex-) + serere "attach, join" (see series). Meaning "put into use" is 1680s. Related: Exerted; exerting.