Not effective; not producing the desired effect; ineffectual
Not producing the desired effect with a minimum use of energy, time, etc.; ineffective
Not having the desired effect
Producing or capable of producing a desired effect.
Find another word for inefficacious. In this page you can discover 6 synonyms, antonyms, idiomatic expressions, and related words for inefficacious, like: ineffective, ineffectual, inefficient, useless, affect and efficacious.