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effectiveness

[ih-fek-tiv-nis, ee-fek‐] / ɪˈfɛk tɪv nɪs, iˈfɛk‐ /
NOUN
persuasiveness
Synonyms
STRONGEST
convincingness persuasiveness strength validity
STRONG
cogency influence validness vigor weight
Antonyms
STRONGEST
inconclusiveness ineffectiveness invalidity weakness
NOUN
ability to produce a result
Synonyms
STRONGEST
capability efficacy efficiency potency power success
STRONG
efficaciousness force forcefulness punch
Antonyms
STRONGEST
failure impotence inability incompetence ineffectiveness inefficiency

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.