Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

Medical Dictionary

opportunistic

play
adjective op·por·tu·nist·ic \-t(y)ü-ˈnis-tik\

Medical Definition of opportunistic

  1. 1:  of, relating to, or being a microorganism that is usually harmless but can become pathogenic when the host's resistance to disease is impaired

  2. 2:  of, relating to, or being an infection or disease caused by an opportunistic organism <Pneumocystis carinii pneumonia and other opportunistic infections that kill AIDS patients—New York Times>





Seen and Heard

What made you want to look up opportunistic? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

February 7, 2016

a slight offense

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image1037863653

Which of the following refers to thin, bending ice, or to the act of running over such ice?

pince-nez spindrift duvet kittly-benders
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ