Synonyms for in efficacious
- abortive
- anticlimactic
- barren
- bootless
- defeasible
- feckless
- feeble
- forceless
- fruitless
- futile
- idle
- impotent
- inadequate
- incompetent
- indecisive
- inefficacious
- inefficient
- inept
- inferior
- innocuous
- inoperative
- invertebrate
- lame
- limited
- neutralized
- nugatory
- null
- null and void
- paltry
- powerless
- spineless
- unable
- unavailing
- unfruitful
- unproductive
- unprofitable
- unsuccessful
- vain
- void
- withered
- worthless
MOST RELEVANT
Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the
Philip Lief Group.