1. (n.) A medicine which preserves or defends against disease; a preventive.

2. (a.) Alt. of Prophylactical.

IUD aegis antacid antidote antiseptic arm guard aseptic backstop bag birth control device boiled buffer bulwark bumper condom contraceptive contraceptive foam copyright counteractant counteractive counteragent counterirritant covering crash helmet cushion custodial dashboard decontaminated defensive deterrent deterring diaphragm discouraging disinfected dodger face mask fender finger guard foot guard forbidding forestalling fostering fuse goggles governor guard guardian guarding guardrail hand guard handrail hard hat helmet hygienic immunizing insulation interlock intrauterine device knee guard knuckle guard laminated glass life preserver lifeline lightning conductor lightning rod mask mudguard neutralizer nose guard nullifier offset oral contraceptive pad padding palladium parental pasteurized patent pessary pilot preclusive preventative preventive prohibitive protecting protective protective clothing protective umbrella remedy rubber safeguard safeguarding safety safety glass safety plug safety rail safety shoes safety switch safety valve sanitary screen screening seat belt sheltering shield shielding shin guard skin spermicidal jelly spermicide sterile sterilized sun helmet the pill tutelary umbrella uninfected vigilant watchful windscreen windshield