Dictionary.com
Thesaurus.com
Synonyms

prophylactic

American  
[proh-fuh-lak-tik, prof-uh-] / ˌproʊ fəˈlæk tɪk, ˌprɒf ə- /

adjective

  1. defending or protecting from disease or infection, as a drug.

  2. preventive or protective.


noun

  1. Medicine/Medical. a prophylactic medicine or measure.

  2. a preventive.

  3. a device, usually a rubber sheath, used to prevent conception or venereal infection; condom.

prophylactic British  
/ ˌprɒfɪˈlæktɪk /

adjective

  1. protecting from or preventing disease

  2. protective or preventive

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

noun

  1. a prophylactic drug or device, esp a condom

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms


Etymology

Origin of prophylactic

First recorded in 1565–75; from Greek prophylaktikós “of guarding,” equivalent to prophylak- (base of prophylássein “to guard beforehand”) + -tikos -tic; see prophylaxis


Explanation

Prophylactic might sound like a prehistoric period when dinosaurs roamed the earth, but it actually describes something that can prevent something negative, such as disease. Prophylactic surgery to remove a mole can prevent skin cancer. If you want to avoid getting sick, you can get a vaccine, take medicine, or have surgery — all of which are considered prophylactic measures. Delve deeper into the history of this four-syllable word and you'll find the Greek term prophulaktikos, which means to "guard before." Prophylactic can also describe a contraceptive used to prevent pregnancy. This use of the word started because condoms, which are prophylactics, were originally designed to prevent disease, not pregnancy.

Keep Reading on Vocabulary.com

Vocabulary lists containing prophylactic

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

The volunteers were divided into two groups: prophylactic arm and therapeutic arm.

From Science Daily ● Sep. 13, 2026

While experts try to lock in a diagnosis, the center reported she’s receiving several prophylactic treatments and they are “cautiously hopeful.”

From Los Angeles Times ● Jul. 28, 2026

Pet owners across the country have been advised they should treat their cats and dogs as a preventative measure every month, known as prophylactic use - although many veterinary organisations have now updated their advice.

From BBC ● Jun. 10, 2026

Schiffman, 29, knew her mom had a prophylactic double mastectomy in 2015 after discovering she had the BRCA1 gene mutation.

From The Wall Street Journal ● Jun. 7, 2026

Lastly, we have to speak of prophylactic measures, which really ought never to be thought of as a separate matter, but always as an essential and most important part of the treatment of neuralgia.

From Neuralgia and the Diseases that Resemble it by Francis E. Anstie

Random Word

Spin the wheel and learn a new word!

Get a word

Vocabulary.com logo
by dictionary.com

Join 14,000,000 vocabulary learners

Start learning new words today on VocabTrainer.
You'll remember them forever.

Start training