n. In general, one who holds the place of another in the performance of any duty or function; one authorized to act in lieu of another, or employed to carry out his will or purposes; the substitute or representative of a superior.n. One who holds an office, civil or military, in subordination to or as the representative of a superior; an officer authorized to perform certain functions in the absence or under the orders of another: as, the lieutenant of the Tower of London; the lord lieutenant of Ireland or of an English county (considered the direct representative of the sovereign).n. In archery, the winner of a lieutenancy in a shooting-match.