efficient

UK: /ɪˈfɪʃ^ənt/ US: /ɪˈfɪʃənt/ ,(i fish′ənt)

WordReference Random House Learner's Dictionary of American English © 2025

ef•fi•cient /ɪˈfɪʃənt/   adj. 

1. performing or functioning effectively with the least waste of time and effort; competent:
   an efficient secretary.

ef•fi•cien•cy /ɪˈfɪʃənsi/  n. [uncountable]
ef•fi•cient•ly, adv. See -fec-.

WordReference Random House Unabridged Dictionary of American English © 2025

ef•fi•cient  (i fish′ənt), adj. 

1. performing or functioning in the best possible manner with the least waste of time and effort;
   having and using requisite knowledge, skill, and industry;
   competent;
   capable:
   a reliable, efficient secretary.
2. satisfactory and economical to use:
   Our new air conditioner is more efficient than our old one.
3. producing an effect, as a cause;
   causative.
4. Business utilizing a particular commodity or product with maximum efficiency (usually used in combination):
   a fuel-efficient engine.

• Latin efficient- (stem of efficiēns), equivalent. to ef- ef- + fic-, combining form of facere to make, do¹ + -ent- -ent
• Middle French)
• Middle English (1350–1400

ef•fi′cient•ly, adv. 
Synonyms

• 1. effectual. See effective. 

Collins Concise English Dictionary © HarperCollins Publishers::

efficient / ɪˈfɪʃənt/ adjective

1. functioning or producing effectively and with the least waste of effort; competent
2. producing a direct effect; causative

Etymology: 14th Century: from Latin efficiēns effecting