c.1200, engoinen, "to prescribe, impose" (penance, etc.), from stem of Old French enjoindre (12c.) "impose (on), inflict; subject to; assign (to)," from Latin iniungere "to join, fasten, attach;" figuratively "to inflict, to attack, impose," from in- "on" (see in-(2)) + iungere "to join" (see jugular). Related: Enjoined; enjoining.