• noun:   remedy that prevents or slows the course of an illness or disease
• noun:   contraceptive device consisting of a thin rubber or latex sheath worn over the penis during intercourse
• adjective:   capable of preventing conception or impregnation
• adjective:   tending to ward off

  Example: "The swastika...a very ancient prophylactic symbol occurring among all peoples- Victor Schultze"

• adjective:   preventing or contributing to the prevention of disease

  Example: "Vaccines are prophylactic"

Related words...