5
usefulness(noun, use, success, worth, efficiency)
4
utility(noun, worth, practicality, usefulness, helpfulness)
4
effectualness(noun, performance, energy, skill, affect)
4
proficiency(noun, power, ability, skill, means)
3
competency(noun, performance, power, energy, ability)
3
effectuality(noun, effect, affect)
3
practicality(noun, worth, usefulness, helpfulness, serviceableness)
3
qualification(noun, force, power, strength, ability)
3
sufficiency(noun, efficiency, productiveness)
3
vigor(noun, force, drive, power, strength)
2
activity(noun, go, drive, power, strength)
2
adequacy(noun, performance, force, power, strength)
2
applicability(practicality, usefulness, helpfulness, utility)
2
avail(practicality, usefulness, helpfulness, utility)
2
cogency(noun, power, strength, energy, influence)
2
facility(noun, power, ability, skill, means)
2
faculty(noun, performance, power, energy, ability)
2
fitness(noun, ability, skill, practicality, usefulness)
2
practicability(worth, practicality)
2
talent(noun, ability, skill, capacity, readiness)
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APASmart Define. (2015). efficacy thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/efficacy/thesaurus/synonyms
ChicagoSmart Define. 2015. "efficacy thesaurus" https://smartdefine.org/efficacy/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, efficacy thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/efficacy/thesaurus/synonyms>.
MLASmart Define. "efficacy thesaurus" 10 April 2015. Web. 21 September 2026. <https://smartdefine.org/efficacy/thesaurus/synonyms>