effective

Etymology
From, from , from.

Adjective

 * 1) Having the power to produce a required effect or effects.
 * 2) Producing a decided or decisive effect.
 * 3) Efficient, serviceable, or operative, available for useful work.
 * 4) Actually in effect.
 * 5)  Having no negative coefficients.
 * 6)  approximate; Not describing the fundamental dynamic changes in some system as they happen.
 * 1) Efficient, serviceable, or operative, available for useful work.
 * 2) Actually in effect.
 * 3)  Having no negative coefficients.
 * 4)  approximate; Not describing the fundamental dynamic changes in some system as they happen.
 * 1) Actually in effect.
 * 2)  Having no negative coefficients.
 * 3)  approximate; Not describing the fundamental dynamic changes in some system as they happen.
 * 1)  Having no negative coefficients.
 * 2)  approximate; Not describing the fundamental dynamic changes in some system as they happen.
 * 1)  Having no negative coefficients.
 * 2)  approximate; Not describing the fundamental dynamic changes in some system as they happen.

Usage notes
Webster's Revised Unabridged Dictionary from 1913 lists and  as synonyms, but all major dictionaries now show that these words now only have different meanings in careful use. Use of both for the other meaning is however widespread enough that Longman's Exam Dictionary, for example, finds it necessary to proscribe the use of one for the other with several examples at each entry and provides the following summary:
 * efficient = working quickly and without waste
 * effective = having the desired effect

Translations

 * Arabic: فَعَّال
 * Belarusian: эфекты́ўны
 * Bulgarian:
 * Catalan: eficaç
 * Chinese:
 * Mandarin:
 * Danish: virksom, effektiv
 * Dutch:, ,
 * Egyptian:
 * Finnish:, , tehoava, , tuloksia tuottava
 * French:
 * German:, ,
 * Gothic: 𐍅𐌰𐌿𐍂𐍃𐍄𐍅𐌴𐌹𐌲𐍃
 * Greek:
 * Ancient: πρακτικός, δραστήριος, ἐνεργής, ἐνεργητικός
 * Hebrew: ,
 * Hungarian:, , , ,
 * Irish: éifeachtach
 * Italian:
 * Kazakh: тиімді, нәтижелі
 * Latin:
 * Latvian: iedarbīgs
 * Malay: berkesan
 * Maori: pekepakihiwi
 * Norwegian: virkningsfull
 * Polish: ,
 * Portuguese: ,
 * Romanian:, , efectent
 * Russian:
 * Sanskrit:
 * Scottish Gaelic: èifeachdach
 * Serbo-Croatian:
 * Cyrillic: учинко̀вит, е̏фектӣван
 * Roman: ,
 * Slovak: účinný
 * Sorbian:
 * Lower Sorbian: statkowny, efektiwny
 * Spanish: ,
 * Swedish:, , verkningsfull
 * Ukrainian: ефекти́вний
 * Welsh:
 * Yiddish: עפֿעקטיוו


 * Bulgarian:
 * Catalan: eficaç
 * Chinese:
 * Mandarin:
 * Danish: effektiv, virksom
 * Dutch:
 * Finnish:
 * French: ,
 * German:
 * Greek:
 * Ancient: ἀνύσιμος, ἀνυστικός
 * Hungarian:, ,
 * Indonesian:
 * Latin:
 * Latvian: iedarbīgs
 * Maori: pekepakihiwi
 * Norwegian: virkningsfull
 * Portuguese:
 * Romanian:
 * Russian:
 * Scottish Gaelic: èifeachdach
 * Swedish:
 * Ukrainian: результати́вний
 * Yiddish: עפֿעקטיוו


 * Bulgarian:
 * Catalan: eficaç
 * Chinese:
 * Mandarin:
 * Finnish:, tehollinen, , käytettävissä oleva
 * French:
 * German: ,
 * Hungarian:, , , , , ,
 * Italian:
 * Norwegian:
 * Portuguese:
 * Romanian: plin de efect,
 * Russian: ,
 * Scottish Gaelic: èifeachdach
 * Slovak: účinný, skutočný
 * Swedish:, ,
 * Tagalog: mapakipakinabang
 * Yiddish: עפֿעקטיוו


 * Bulgarian:
 * Catalan:
 * Chinese:
 * Mandarin:
 * Dutch:
 * Finnish:, voimassa oleva
 * French:
 * German: ,
 * Hungarian:, , hatályban van, érvényben van
 * Indonesian:
 * Norwegian: virksom
 * Polish:
 * Portuguese:
 * Russian: ,
 * Swedish: träder i kraft


 * Ido:

Noun

 * 1)  a soldier fit for duty