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]