Main Entry: ¹ef·fec·tive

Pronunciation: \i-ˈfek-tiv, e-, ē-, ə-\

Function: adjective

Date: 14th century

1 a : producing a decided, decisive, or desired effect <an effective policy> b : impressive, striking <a gold lamé fabric studded with effective…precious stones — Stanley Marcus>
2 : ready for service or action <effective manpower>
3 : actual <the need to increase effective demand for goods>
4 : being in effect : operative <the tax becomes effective next year>
5 of a rate of interest : equal to the rate of simple interest that yields the same amount when the interest is paid once at the end of the interest period as a quoted rate of interest does when calculated at compound interest over the same period — compare nominal 4

— ef·fec·tive·ness noun

— ef·fec·tiv·i·ty \ˌe-ˌfek-ˈti-və-tē, i-, ē-, ə-\ noun

synonyms 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 <an effective rebuttal>. effectual suggests the accomplishment of a desired result especially as viewed after the fact <the measures to stop the pilfering proved effectual>. efficient suggests an acting or a potential for action or use in such a way as to avoid loss or waste of energy in effecting, producing, or functioning <an efficient small car>. efficacious suggests possession of a special quality or virtue that gives effective power <a detergent that is efficacious in removing grease>.