adj. 25B6; adjective INEFFECTIVE, ineffectual, inefficacious, vain, futile, useless, unsuccessful, fruitless, profitless, unprofitable, to no avail, abortive; archaic bootless.
effective.
UNAVAILING
Meaning of UNAVAILING in English
Concise Oxford thesaurus English vocabulary. Краткий оксфордский словарь английского языка тезаурус. 2012