prophylactic

1. A medicine which preserves or defends against disease; a preventive.Examples: "It is not clear whether such education is to be directed to homosexuals (for whom prophylactics are not a contraceptive) or to heterosexuals as well (for whom prophylactics are a contraceptive)."; "Given the widespread use of coitus interruptus and male prophylactics as contraceptive practices in France […]"; "Some men put the prophylactic on just the tip of the penis: this is a mistake, because the prophylactic will come off."Synonyms: condom, cum catcher, rubberUSspecifically

2. (figuratively) Any device or mechanism intended to prevent harmful consequences.Examples: "The securities laws are a prophylactic against stock fraud."; "Since tere are increasingly powerful anti-free speech tendencies in the left in general and in the Lesbian and Gay movements in particular in the form of the antiporn movement and other tendencies, I will quote extensively from the second chapter of On Liberty, "On The Liberty Of Thought And Discussion," as a valuable and much needed prophylactic to these trends."figuratively