Having the power to produce a required effect or effects. / Producing a decided or decisive effect. / Efficient, serviceable, or operative, available for useful work. / Actually in effect.

(military) a soldier fit for duty

Third-person singular simple present indicative form of effect

plural of effect

present participle of effect

Causative, effective.

with more or less the meaning of

plural of effectiveness

plural of effecter

(psychology) effective interaction with one's environment