effective

adjective

successful in achieving desired effect

Wiktionary

Pronunciation: /ɪˈfɛktɪv/ / /əˈfɛktɪv/ / /əˈfektɪv/

adj

Etymology: Etymology tree Proto-Indo-European *h₁éǵʰ Proto-Indo-European *-s Proto-Indo-European *h₁éǵʰs Proto-Italic *eks Latin ex Latin ef- Proto-Indo-European *dʰeh₁k- Proto-Indo-European *-yéti Proto-Indo-European *dʰh₁kyéti Proto-Italic *θakjō Proto-Italic *fakjō Latin faciō Latin efficiō Proto-Indo-European *-wós Proto-Indo-European *-iHwósder. Latin -īvus Latin effectivusbor. French effectifder. English effective From French effectif, from Latin effectīvus (“productive; effective”), from efficiō (“to make; to bring about”), equivalent to effect + -ive.

Having the power to produce a required effect or effects.
“The pill is an effective method of birth control.”
“"Capital idea; we'll go together and complain: two will be more effective," suggested Mr. Belting.”
Producing a decided or decisive effect.
“The president delivered an effective speech!”
“Whosoever is an effective, real cause of doing his neighbour wrong, is criminal.”
Efficient, serviceable, or operative, available for useful work.
“How long does it take to make a bunch of civilians an effective military force?”
“My effective income after taxes and child support is $500 a month.”
Actually in effect.
“effective immediately”
“The curfew is effective at midnight.”
Having no negative coefficients.
Such that no group element acts trivially.
approximate; Not describing the fundamental dynamic changes in some system as they happen.

noun

a soldier fit for duty
“The Army of the West reached Corinth sometime after the battle of Shiloh. We were 15,000 effectives, and brought Beauregard's effective force up to 45,000 men.”