Children's, Intermediate and Advanced Online English Dictionary & Thesaurus

Comprehensive
Dictionary Suite
Help
Help
Help
 
Advanced Dictionary    
Display options
Show syllables
Show Lookup History
Double-Click Lookup
  Show Spanish support
  Show Word Combinations
 
Pronunciation
Wordsmyth
  Phonics
  IPA
 
Entry formats
Standard
  Classic
 
Lookup History
efficacious

ef·fi·ca·cious

efficacious

 
pronunciation:
e f keI shihs
part of speech: adjective
definition: causing or capable of causing a desired result; effectual; effective.
The treatment showed signs of being efficacious for this group of patients.
antonyms:
ineffective, inefficacious
similar words:
effective, efficient, fruitful, valid
derivations: efficaciously (adv.), efficaciousness (n.)