prophylactic

1 of 2

adjective

pro·​phy·​lac·​tic ˌprō-fə-ˈlak-tik 

also

ˌprä- 

1

: guarding from or preventing the spread or occurrence of disease or infection

2

: tending to prevent or ward off : preventive

prophylactically

ˌprō-fə-ˈlak-ti-k(ə-)lē 

also ˌprä-

adverb

prophylactic

2 of 2

noun

: something prophylactic

especially : a device and especially a condom for preventing sexually transmitted infection or conception

Synonyms of prophylactic

Adjective

• preventive
• preventative

Examples of prophylactic in a Sentence

Adjective

the prophylactic use of antibiotics

the many prophylactic measures that city officials could have taken to reduce the scope of the disaster

Recent Examples on the Web

Adjective

When a friend mentioned his brother died not from multiple myeloma but from an infection during treatment, Brown asked the AI about defensive measures and learned about prophylactic antibodies through monthly infusions. —Craig S. Smith, Forbes.com, 21 Jan. 2026

It's also used as a prophylactic medication — as in Trump's case — in about one in seven older Americans. —Michal Ruprecht, NPR, 2 Jan. 2026

Noun

Because vitamin K shots have been widely given in the U.S. for more than 60 years, Hand said parents may not understand the risk of forgoing the prophylactic. —Kaitlin Sullivan, NBC news, 8 Dec. 2025

In other words: Beijing is taxing the prophylactics, buying the androids, and seeing what happens next. —Newsweek Editors, MSNBC Newsweek, 5 Dec. 2025

Word History

Etymology

Adjective

borrowed from Medieval Latin prophylacticus, borrowed from Greek prophylaktikós, from prophylakt-, stem in nominal derivation of prophylássein "to keep guard before a place, be on guard, (middle voice) to be on one's guard against, take precautions against" + -ikos -ic entry 1 — more at prophylaxis

Noun

borrowed from Late Latin prophylacticon "protective measure against disease," borrowed from Late Greek prophylaktikón, noun derivative from neuter of Greek prophylaktikós prophylactic entry 1

First Known Use

Adjective

1574, in the meaning defined at sense 1

Noun

circa 1641, in the meaning defined above

Rhymes for prophylactic

• chemotactic
• chiropractic
• isotactic
• anaphylactic
• extragalactic
• intergalactic
• stereotactic
• climactic
• didactic
• galactic
• syntactic
• lactic

Kids Definition

prophylactic

1 of 2 adjective

pro·​phy·​lac·​tic ˌprō-fə-ˈlak-tik 

1

: guarding from or preventing the spread or occurrence of disease or infection

2

: tending to prevent or ward off

prophylactic

2 of 2 noun

: something prophylactic

especially : a device and especially a condom for preventing infection or pregnancy

Medical Definition

prophylactic

1 of 2 adjective

pro·​phy·​lac·​tic

ˌprō-fə-ˈlak-tik also ˌpräf-ə-

1

: guarding from or preventing the spread or occurrence of disease or infection

prophylactic therapy

2

: tending to prevent or ward off : preventive

prophylactically

-ti-k(ə-)lē 

adverb

prophylactic

2 of 2 noun

: something (as a medicinal preparation) that is prophylactic

especially : a device and especially a condom for preventing venereal infection or conception

Legal Definition

prophylactic

adjective

pro·​phy·​lac·​tic ˌprō-fə-ˈlak-tik, ˌprä- 

: designed or tending to prevent harm or wrong

a prophylactic rule against profiting from inside information