Definition of efficacious
: having the power to produce a desired effect
an efficacious remedy
Test Your Vocabulary
Words Named After People
-
- Namesake of the leotard, Jules Léotard had what profession?

Test your vocabulary with our 10-question quiz!
TAKE THE QUIZ
A daily challenge for crossword fanatics.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Share efficacious
Time Traveler for efficacious
The first known use of efficacious was in 1528
See more words from the same year