efficient

Meanings

Adjective

• making good, thorough, or careful use of resources; not consuming extra. Especially, making good use of time or energy
• expressing the proportion of consumed energy that was successfully used in a process; the ratio of useful output to total input
• causing effects, producing results; bringing into being; initiating change (rare except in philosophical and legal expression efficient cause = causative factor or agent)
• effective

Noun

• a cause; something that causes an effect

Related

Opposite words

• inefficient

Origin

• 1398, “making,” from Old French, from Latin efficientem, nominative efficiēns, participle of efficere (see effect). Meaning “productive, skilled” is from 1787. Efficiency apartment is first recorded 1930, American English.