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1. Being effective without wasting time, effort or expense
   "an efficient production manager"; "efficient engines save gas"
    
2. Able to accomplish a purpose; functioning effectively
   "an efficient secretary"; "the efficient cause of the revolution";
   - effective

See also: businesslike, competent, cost-effective, cost-efficient, economic, economical, effective, effectual, efficacious, expeditious, high-octane, high-test [US], streamlined

Antonym: inefficient

Encyclopedia: Efficient