"occasionally" | Definition and Related Words

Adverb

Sporadically and infrequently (synset 400021667)
"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"

same as: at times, from time to time, now and again, now and then, on occasion, once in a while