efficacious

== English == === Etymology === From Old French efficacieux, from Latin efficāx (“efficacious”) +‎ -ous, from efficere (“to effect, to accomplish”); see effect. === Pronunciation === (Received Pronunciation) IPA(key): /ˌɛf.ɪˈkeɪ.ʃəs/ (General American) IPA(key): /ˌɛf.əˈkeɪ.ʃəs/ (General Australian) IPA(key): /ˌef.əˈkæɪ.ʃəs/ Rhymes: -eɪʃəs === Adjective === efficacious (comparative more efficacious, superlative most efficacious) (formal) Effective; possessing efficacy. [from 1520s] Synonym: effective Antonym: inefficacious ==== Derived terms ==== ==== Related terms ==== ==== Translations ==== ==== Further reading ==== “efficacious”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC. William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “efficacious”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC. “efficacious”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.