Definitions
American Heritage® Dictionary of the English Language, Fourth Edition
- adj. Producing or capable of producing a desired effect. See Synonyms at effective.
Century Dictionary and Cyclopedia
- Producing the desired effect; having power adequate to the purpose intended; effectual in operation or result.
- Synonyms Efficient, Effectual, etc. (see effective); active, operative, energetic.
Wiktionary
- adj. effective
GNU Webster's 1913
- adj. Possessing the quality of being effective; productive of, or powerful to produce, the effect intended.
WordNet 3.0
- adj. marked by qualities giving the power to produce an intended effect
- adj. producing or capable of producing an intended result or having a striking effect
Etymologies
- From Old French efficacieux, from Latin efficax ("efficacious"), from efficere ("to effect, accomplish, to"); see effect. (Wiktionary)
- From Latin efficāx, efficāc-, from efficere, to effect; see effect. (American Heritage® Dictionary of the English Language, Fourth Edition)
Examples
“The special grace which we refer to as efficacious is sometimes called irresistible grace.”
“Those, however, which follow the last judgment, are simply and absolutely called efficacious volition and nolition, to which the effect succeeds.”
“efficacious' - despite the fact that the chemist sells the medicines.”
“How many songs do you know that use the word "efficacious" without missing a beat?”
“Time is not by itself "efficacious"; that is, the mere passage of time does not augment or diminish the capacities of anything and, in particular, it does not enhance or decrease an agent's powers or abilities.”
“The term “apotropaic” is a broad term referring to something intended to ward off evil, whereas the word “magic” in this case, simply refers to any ritualized behavior believed by its practitioners to be efficacious, that is, effective. [”
“Company manager Jong Song Ho, 38, told KCNA that the drink was particularly "efficacious" among workers at a thermal power station, smelter and at medical institutions.”
“Framingham-based GTC Biotherapeutics 'ATryn, an anti-clotting medicine made from the milk of genetically altered goats, was deemed safe and "efficacious" by an FDA advisory panel.”
“The CIA's own Inspector General wrote that waterboarding was not "efficacious" in producing information”
“Army Reserve strategic intelligence officer who taught prisoner interrogation and military law for 18 years with the Sixth Army Intelligence School wrote that waterboarding was not "efficacious" in producing information”
Lists
These user-created lists contain the word ‘efficacious’.
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501
Classic
aberration, abstruse, anomaly, assiduous, august, banal, boisterous, dulcet, epitome, impudent, insolent, mellifluous and 401 more...
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Interesting words
A list of words that are odd or words that I have looked up.
concupiscence, brize, scree, scoria, forestaff, spanaemia, valetudinarianism, distasture, pyrethrum, laudanum, gentian, bicameral and 11184 more...
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501
Classic
abhor, mirth, obtuse, iota, vex, irk, teem, pith, moot, mete, ire, bane and 401 more...
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501
Classic
irk, teem, blight, pith, moot, mete, ire, bane, bilk, boor, elan, ado and 401 more...
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501
Classic
aberration, abstruse, anomaly, assiduous, august, banal, boisterous, dulcet, epitome, impudent, insolent, mellifluous and 401 more...
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Words I Used to Know
Words that make you go "I know that word...what the heck does it mean?!?
pulchritude, sanguine, trenchant, picaresque, gloaming, perfidious, confabulation, epiphany, importune, fulminate, efficacious, maladroit and 111 more...
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Words build meanings from origins( et...
These come from gamma meditation ,I think.
discursive, exogenous, machinations, purportedly, sumptuous, congruity, cantankerous, incongruous, festoon, hessian, ratiocinative, stratigraphic and 2046 more...
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Ballardian
All things descriptive from JG
Ballardoperation mindfuck, pataphysics, wahrheitssensible..., polymorphism, postprandial, covalent, stygian, lucus a non lucendo, kafkaesque, leitmotif, fugacious, ablate and 77 more...
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GRE Study guide
Going through the Magoosh website, words I pulled from the verbal section. 2012.
magnanimous, correlate, anglicized, simulacrum, tantamount, obsequiousness, subterfuge, vehement, vociferous, benign, concomitant, veracity and 83 more...
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New Words
idiopathic, explicate, expiate, pellucid, exogenous, pelagic, manque, salonniere, pedantic, expatiate, cyclamen, peregrination and 83 more...
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trait treats
efficacious, garish, implacable, intrepid, soporific, somniferous, fetid, lurid, undaunted, debonair, quiescent, fabulist
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Words for deinonychus
If you find a word that you want to share with me, this is a good place for it. I will try to look after it.
psychotronics, dolichocephalic, efficacious, scabrous, sympatidig, Ischnoceran, Amblyceran, Rhynchophthiran, Anopluran, Fahrenholz' Rule, Zlotorzycka's Rule, Eichler's Rule and 69 more...
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big book gre
abase, abbess, abbey, abbot, abdicate, abdomen, abdominal, abduction, abed, aberration, abet, abeyance and 6691 more...
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gre2
aberrant, aberration, aboveboard, abrasive, abstemious, acme, admonish, affable, affluent, alacrity, allegory, alleviate and 1843 more...
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magoosh1
aberration, aboveboard, abysmal, ace, affable, aghast, alacrity, ambiguous, ambivalent, ameliorate, amenable, amiable and 215 more...
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SAT words
abase, abate, abet, abject, abjure, abrogate, abscond, abstruse, accolade, accommodating, accost, accretion and 202 more...
Tweets
Looking for tweets for efficacious.

gangerh Lily The Pink!!
'... the saviour of the human race
for she invented medicinal compound
most efficacious .....' Mar 2, 2008