The Collaborative International Dictionary of English v.0.48:

contraceptive \contraceptive\ adj.
   capable of preventing conception or impregnation; as,
   contraceptive devices and medications.

   Syn: prophylactic.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

contraceptive \contraceptive\ n.
   a substance or device used to prevent conception.

   Syn: preventive, preventative, contraceptive device,
        prophylactic device, prophylactic.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

contraceptive
    adj 1: capable of preventing conception or impregnation;
           "contraceptive devices and medications" [syn:
           contraceptive, prophylactic, antifertility]
    n 1: an agent or device intended to prevent conception [syn:
         contraceptive, preventive, preventative,
         contraceptive device, prophylactic device, birth
         control device]

Moby Thesaurus II by Grady Ward, 1.0:

75 Moby Thesaurus words for "contraceptive":
   IUD, aegis, arm guard, backstop, bag, birth control device, buffer,
   bulwark, bumper, condom, contraceptive foam, copyright,
   crash helmet, cushion, dashboard, diaphragm, dodger, face mask,
   fender, finger guard, foot guard, fuse, goggles, governor, guard,
   guardrail, hand guard, handrail, hard hat, helmet, insulation,
   interlock, intrauterine device, knee guard, knuckle guard,
   laminated glass, life preserver, lifeline, lightning conductor,
   lightning rod, mask, mudguard, nose guard, oral contraceptive, pad,
   padding, palladium, patent, pessary, pilot, preventive,
   prophylactic, protective clothing, protective umbrella, rubber,
   safeguard, safety, safety glass, safety plug, safety rail,
   safety shoes, safety switch, safety valve, screen, seat belt,
   shield, shin guard, skin, spermicidal jelly, spermicide,
   sun helmet, the pill, umbrella, windscreen, windshield