1. \Proph`y*lac"tic\, n. [Cf. F. prophylactique.] (Med.) A medicine which preserves or defends against disease; a preventive

2. \Proph`y*lac"tic\, Prophylactical\Proph`y*lac"tic*al\, a. [Gr. ?, fr. ? to guard against; ? before + ? to guard: cf. F. prophylactique.] (Med.) Defending or preserving from disease; preventive. --Coxe.

Also: -

3. adj 1: capable of preventing conception or impregnation; "contraceptive devices and medications" [syn: contraceptive, antifertility] 2: tending to ward off; "the swastika....a very ancient prophylactic symbol occurring among all peoples"- Victor Schultze [syn: cautionary, preventive] 3: preventing or contributing to the prevention of disease; "preventive medicine"; "vaccines are prophylactic"; "a prophylactic drug" [syn: preventive, preventative] n 1: remedy that prevents or slows the course of an illness or disease; "the doctor recommended several preventatives" [syn: preventive, preventative] 2: contraceptive device consisting of a thin rubber or latex sheath worn over the penis during intercourse [syn: condom, rubber, safety, safe]