Synonyms of inefficacious in English:

inefficacious


See definition of inefficacious

adjective

1‘the old way of doing things was suddenly inefficacious’

SYNONYMS

ineffective, unsuccessful, non-successful, unproductive, fruitless, profitless, unprofitable, abortive, failed, futile, purposeless, worthless, useless, ineffectual, inefficient, inadequate, vain, unavailing, to no effect

idle, feeble, weak, inept, lame

archaic bootless

rare unfructuous, inutile

ANTONYMS

efficacious