3
in force(adjective, strong, power, valid, legal)
3
power(strong, energetic, active, vigorous, controlling)
3
proficient(adjective, tough, effective, adept, effectual)
3
significant(adjective, strong, important, powerful, useful)
3
sound(reasonable, sensible, rational, wise, shrewd)
3
stiff
3
symbiotic(useful, beneficial, advantageous)
3
winning
2
almighty(strong, power, energetic, powerful, vigorous)
2
available(adjective, strong, power, valid, legal)
2
dominant(adjective, strong, energetic, important, powerful)
2
dynamic(adjective, strong, tough, energetic, powerful)
2
economic(adjective, tough, energetic, effective, adept)
2
expedient(sensible, wise, shrewd, utility)
2
fruitful
2
functioning(moving, active, effective, running, alive)
2
impelling(moving, active, effective, running, alive)
2
infallible(adjective, dependable, unerring)
2
influencing
2
judicious(adjective, sensible, thoughtful, wise, shrewd)
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APASmart Define. (2015). efficacious thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/efficacious/thesaurus/synonyms
ChicagoSmart Define. 2015. "efficacious thesaurus" https://smartdefine.org/efficacious/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, efficacious thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/efficacious/thesaurus/synonyms>.
MLASmart Define. "efficacious thesaurus" 13 October 2015. Web. 22 September 2026. <https://smartdefine.org/efficacious/thesaurus/synonyms>