of leave-of leave.-of or pertaining to that side of the body in man on which the muscular action of the limbs is usually weaker than on the other side; -- opposed to right, when used in reference to a part of the body; as, the left hand, or arm; the left ear. also said of the corresponding side of the lower animals.-that part of surrounding space toward which the left side of one's body is turned; as, the house is on the left when you face north.-those members of a legislative assembly (as in france) who are in the opposition; the advanced republicans and extreme radicals. they have their seats at the left-hand side of the presiding officer. see center, and right.