[proh-fuh-lak-tik, prof-uh-]


defending or protecting from disease or infection, as a drug.
preventive or protective.


Medicine/Medical. a prophylactic medicine or measure.
a preventive.
a device, usually a rubber sheath, used to prevent conception or venereal infection; condom.

Nearby words

  1. prophesy,
  2. prophet,
  3. prophetess,
  4. prophetic,
  5. prophets,
  6. prophylactic treatment,
  7. prophylaxis,
  8. propine,
  9. propinquity,
  10. propiomazine

Origin of prophylactic

1565–75; < Greek prophylaktikós of guarding, equivalent to prophylak- (base of prophylássein to guard beforehand) + -tikos -tic. See prophylaxis

Related formspro·phy·lac·ti·cal·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for prophylactic

British Dictionary definitions for prophylactic



protecting from or preventing disease
protective or preventive


a prophylactic drug or device, esp a condom

Word Origin for prophylactic

C16: via French from Greek prophulaktikos, from prophulassein to guard by taking advance measures, from pro- ² + phulax a guard

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

Word Origin and History for prophylactic



1570s, originally of medicines, "that tends to prevent disease," from Middle French prophylactique (16c.) and directly as a Latinized borrowing of Greek prophylaktikos "precautionary," from prophylassein "keep guard before, ward off, be on one's guard," from pro- "before" (see pro-) + phylassein, Ionic variant of phylattein "to watch over, to guard," but also "cherish, keep, remain in, preserve" (see phylactery).

The noun is first recorded 1640s, "a medicine or treatment to prevent disease;" meaning "condom" is from 1943, replacing earlier preventive (1822), preventative (1901). Condoms originally were used more to thwart contagious disease than to prevent pregnancy.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for prophylactic


[prō′fə-lăktĭk, prŏf′ə-]


A prophylactic agent, device, or measure, such as a vaccine or drug.
A contraceptive device, especially a condom.


Acting to defend against or prevent something, especially disease; protective.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.