Princeton's WordNet

1. occasionally, on occasion, once in a while, now and then, now and again, at times, from time to time(adverb)

   now and then or here and there

   "he was arrogant and occasionally callous"; "open areas are only occasionally interrupted by clumps of trees"; "they visit New York on occasion"; "now and again she would take her favorite book from the shelf and read to us"; "as we drove along, the beautiful scenery now and then attracted his attention"

Wiktionary

1. once in a while(Adverb)

   Occasionally; sometimes.

• nou en danAfrikaans
• قَليلا، بين حينٍ وآخر، أحْياناArabic
• понякогаBulgarian
• de vez em quandoPortuguese (BR)
• čas od časuCzech
• zuweilenGerman
• en gang imellemDanish
• πού και πούGreek
• de vez en cuandoSpanish
• mõnikordEstonian
• گهگاهFarsi
• silloin tällöinFinnish
• de tempsà autreFrench
• מִדֵי פַּעַםHebrew
• कभी-कभी, समय-समय परHindi
• povremenoCroatian
• néha(napján)Hungarian
• kadang-kadangIndonesian
• endrum og einsIcelandic
• ogni tanto, di quando in quandoItalian
• 時折Japanese
• 가끔Korean
• kartkartėmisLithuanian
• šad un tad; paretamLatvian
• sekali-sekalaMalay
• af en toeDutch
• en sjelden gang, iblantNorwegian
• od czasu do czasuPolish
• گهگاهPersian
• كله كلهPashto
• de vez em quandoPortuguese
• din când în cândRomanian
• время от времени, иногдаRussian
• zčasu na časSlovak
• tu in tamSlovenian
• povremenoSerbian
• då och då, en och annan gångSwedish
• บางครั้งบางคราวThai
• arasıra, bazenTurkish
• 偶爾Chinese (Trad.)
• час від часу, інколиUkrainian
• کبھي کبھارUrdu
• thi thoảngVietnamese
• 偶尔Chinese (Simp.)