- Afrikaans: ketter, ketters pl
- Albanian: heretik (sq) m, heretike f
- Arabic: مُلْحِد m (mulḥid), مُلْحِدَة f (mulḥida)
- Armenian: հերետիկոս (hy) (heretikos)
- Aromanian: eretico m
- Azerbaijani: bidətçi
- Belarusian: ерэты́к m (jeretýk), ерэты́чка f (jeretýčka)
- Bulgarian: ерети́к (bg) m (eretík), ерети́чка f (eretíčka)
- Catalan: heretge (ca) m or f
- Chinese:
- Mandarin: 異端/异端 (zh) (yìduān)
- Czech: kacíř (cs) m, kacířka f
- Danish: kætter c
- Dutch: ketter (nl) m
- Esperanto: herezulo, herezulino (female)
- Estonian: ketser
- Faroese: trúarvillingur m, trúvillingur m
- Finnish: harhaoppinen, kerettiläinen (fi), toisinajattelija (fi)
- French: hérétique (fr) m or f
- Georgian: მწვალებელი (mc̣valebeli), ერეტიკოსი (ereṭiḳosi)
- German: Ketzer (de) m, Ketzerin (de) f, Häretiker (de) m, Häretikerin (de) f, Abweichler (de) m, Abweichlerin (de) f
- Greek: αιρετικός (el) m (airetikós), αιρετική (el) f (airetikí)
- Ancient: αἱρετικός m (hairetikós)
- Hebrew: כּוֹפֵר (he) m (kofér), כּוֹפֶרֶת m (koféret), אֶפִּיקוֹרוֹס (he) m (epikóros), אֶפִּיקוֹרֶס (he) m (epikóres), מִין (he) m (mín)
- Hindi: विधर्मी (hi) m (vidharmī)
- Hungarian: eretnek (hu)
- Indonesian: bida'ah
- Irish: eiriceach m
- Italian: eretico (it) m, eretica (it) f
- Japanese: 異端者 (いたんしゃ, itansha)
- Kazakh: бидғатшы (bidğatşy)
- Korean: 이단자(異端者) (idanja), 이교도(異敎徒) (igyodo)
- Kyrgyz: бидъатчы (bidatcı), еретик (ky) (yeretik)
- Latin: haereseus m (Mediaeval), haeresiacus m (Mediaeval), haereticus m (Ecclesiastical)
- Latvian: ķeceris m
- Lithuanian: eretikas m
- Macedonian: криво́верец m (krivóverec), криво́верник m (krivóvernik), ере́тик m (erétik)
- Maori: heretiki
- Norwegian:
- Bokmål: kjetter (no) m, heretiker m, vranglærer m
- Nynorsk: kjettar m, heretikar m, ranglærar m
- Occitan: eretic (oc) m, erètge (oc) m
- Old Church Slavonic:
- Cyrillic: еретикъ m (eretikŭ)
- Old Czech: cafúr m
- Persian: زندیک (fa) (zandik), زندیق (fa) (zendiq)
- Polish: heretyk (pl) m, heretyczka (pl) f, kacerz (pl) m (archaic), kacerka f
- Portuguese: herege (pt) m or f
- Romanian: eretic (ro) m
- Russian: ерети́к (ru) m (jeretík), ерети́чка (ru) f (jeretíčka)
- Scottish Gaelic: saobh-chreidmheach m
- Serbo-Croatian:
- Cyrillic: кривоверан m, кривоверна f, јеретик m
- Roman: krivoveran (sh) m, krivoverna f, jeretik (sh) m
- Slovak: kacír m, kacírka f, heretik m, heretička f
- Slovene: krivoverec (sl) m, krivoverka f, heretik (sl) m, heretičarka f
- Spanish: hereje (es) m or f
- Swedish: kättare (sv) c, heretiker (sv) c
- Tagalog: erehe
- Tajik: бидъаткор (bidʾatkor)
- Tocharian B: tīrthe ?
- Turkish: zındık (tr), kâfir (tr)
- Ukrainian: єрети́к m (jeretýk), єрети́чка f (jeretýčka)
- Uzbek: bidʻatchi
- Vietnamese: dị giáo
- Volapük: häretan (vo), hihäretan (male), jihäretan (female)
- Yiddish: אַפּיקורס m (apikoyres), מין m (min)
|