Definition of "efficient" in English

adjective

1. Making good, thorough, or careful use of resources; not consuming extra. Especially, making good use of time or energy.

   • An efficient process would automate all the routine work.
   • Our cleaners are almost too efficient: they throw away anything left out on a desk.

2. Expressing the proportion of consumed energy that was successfully used in a process; the ratio of useful output to total input.

   • The motor is only 20% efficient at that temperature.

3. Causing effects, producing results; bringing into being; initiating change (rare except in philosophical and legal expression efficient cause = causative factor or agent).

   • Ownership, maintenance, or use of the automobile need not be the direct and efficient cause of the injury sustained

4. (proscribed, old use) effective, efficacious

noun

1. (obsolete) A cause; something that causes an effect.