efficacious, adj. 1. effective, effectual, operative, prevailing, productive, efficient, Archaic, prevalent; competent, proficient, adept, masterful, expert, masterly, Fr. au fait; skillful, adroit, deft.
2. powerful, potent, sovereign, forceful, forcible, strong, weighty; dynamic, vigorous, energetic, active, Archaic, virtuous; sound, valid, reliable, believable; capable, able, qualified, adequate, sufficient.
efficacy, n. 1. effectiveness, effectualness, productiveness, efficiency, Scot. and North Eng. feck, Archaic. prevalent; competence, competency, proficiency, adeptness; mastery, expertise, expertness, knowhow, savoir-faire.
2. capacity, potentiality, capability, capableness, ability, ableness; power, potency, virtue, force, vigor, strength, value, weight; validity, soundness, reliability, believability.
efficiency, n. 1. competence, competency, fitness, fittedness, qualification, eligibility, preparedness, readiness; capability, capableness, commensurability, the stuff, Inf. what it takes, U.S. Inf. the goods; mastery, authority, expertness, expertise; proficiency, adeptness, address, finesse, facility, polish; practice, experience, know-how, savoir-faire; skillfulness, adroitness, deftness, dexterity, dexterousness.
2. productiveness, productivity, generation, efficaciousness, effectiveness, causativeness; potency, power, high-poweredness, Literary, puissance, energy, vigor, dynamism.
3. apartment, room, flat.
efficient, adj. 1. efficacious, effectual, effective, effecting, valid, active, operative, operant; causative, productive, producing, generative, generating, assembly line; potent, powerful, high-powered, puissant, energetic, vigorous, dynamic.
2. competent, fit, fitted, SI. on the ball, qualified, eligible, prepared, well-grounded, trained, ready; capable, commensurate, equal to, Inf up to; expert, masterful, masterly, Inf. crack, SI. crackerjack, Inf. whiz-bang, Brit. SI. whizzo; proficient, adept, accomplished, polished, practiced, experienced, Fr. au fait; clever, adroit, slick, deft, skillful, talented, dexterous.
3. economical, thrifty, saving.
effigy, n. image, likeness, representation, resem blance; icon, idol; figure, figurine, doll, straw man, scarecrow.
effluence, n. 1. discharge, emission, efflux, effusion, exhalation, Obs. vent.
2. outflow, outflowing, outpour, outpouring, emanation, effluent.
effluvium, n. fume, exhalation, exhaust; miasma, mephitis, Archaic, malaria; gas, vapor; reek, stench, odor.
efflux, n. See - effluence (defs. 1,2).
effort, n. 1. exertion, striving, impulse, conatus, nisus; struggle, strain, stress, application, exercitation; trouble, pains, grind, push; work, labor, toil, travail, industry; sweat of one's brow, Inf. elbow grease, muscle, back; practice, discipline, training, exercise, drill.
2. attempt, venture, endeavor, essay, Fr. coup d'essai', try, aim, trial, test; Inf. go, Inf. pull, Inf. the old college try, SI. crack, SI. whack.
3. achievement, feat, exploit, attainment, deed, act; bold stroke, tour de force, opus.
effortless, adj. 1. easy, facile, simple, Scot. eath, downhill, like taking candy from a baby, easy as 1,2,3 or A,B,C, easy as pie; a piece of cake, a pushover, Inf. a snap, a cinch, smooth or clear sailing; All SI. gut, cushy, cinchy; no sweat, child's play, a breeze, duck soup; nothing to it.