adj ·Rare ·Advanced level

Definitions

Adjective

1. 1
   Incapable of having the intended consequence.
2. 2
   Not effective.

Adjective

1. 1
   lacking the power to produce a desired effect wordnet

Synonyms

All synonyms

abortivebarrenbootlesscounterproductiveeffeteempty

Antonyms

All antonyms

effectiveefficaciousthriftyeffectuated

Etymology

From in- + efficacious.