effective

/i-ˈfek-tiv/

Middle English effectif, borrowed from Late Latin effectīvus "producing a result, efficient," going back to Latin, "involving an end product," from effectus, past participle of efficere "to make, bring about, produce, carry out" + -īvus -ive

adjective

  1. producing a decided, decisive, or desired effect

  2. impressive, striking

  3. being in effect : operative

an effective policy

a gold lamé fabric studded with effective … precious stones

effective effectual efficient efficacious mean producing or capable of producing a result. effective stresses the actual production of or the power to produce an effect. effectual suggests the accomplishment of a desired result especially as viewed after the fact.

noun

  1. one that is effective; especially : a soldier equipped for duty

noun

  1. the day when a law, rule, contract, etc., starts to be used