Synonyms for efficacy
Most common
All synonyms
Noun
1. Effectiveness
effectiveness, usefulness, validity, efficiency, capability, ability, weight, virtue, energy, force
Other
Definitions
- n. 1
The ability to produce a desired effect under ideal testing conditions.
Related words
Forms
- Plural
- efficacies → effectivenesses, usefulnesses, validities, efficiencies…
Choose the right word
Efficacy is the power to produce an intended effect as shown in the production of it; as, the efficacy of a drug.
J. C. Fernald, English Synonyms and Antonyms (1914)
Example sentences
- efficiency Which is more important, creativity or efficiency?
- effectiveness Don't doubt the effectiveness of this medicine.
- validity Verify the institution's accreditation validity.
- usefulness He has doubts regarding astrology's usefulness.
Popularity over time
| Word | 1850 → 2019 | Trend |
|---|---|---|
| efficacy | rising | |
| efficiency | falling | |
| effectiveness | steady | |
| validity | falling | |
| usefulness | falling | |
| efficacity | falling |
Use in printed books, per decade from 1850 to 2019.
By length
- 5 letters
- force1
- 6 letters
- energy3, weight1, virtue2
- 7 letters
- ability4
- 8 letters
- validity4
- 10 letters
- efficiency4, capability5, usefulness3, efficacity
- 13 letters
- effectiveness4
- 15 letters
- efficaciousness
The small number after each word is its number of syllables (energy3 = 3 syllables).