Synonyms for Occasionally:

adv.

circumstantially (adverb)
incidentally, uncertainly, Inferentially, presumptively, indirectly, eventually, circumstantially, inconclusively.
every now and then (adverb)
uncommonly, infrequently, from time to time, at times, on occasion, sporadically, once in a while, at random, seldom, every so often, periodically, sometimes, hardly, now and again, irregularly.
infrequently (adverb)
rarely, sporadically, infrequently, unusually, uncommonly, sparsely, oddly.

adv

at times (adverb)
intermittently.
circumstantially (adverb)
incidentally, uncertainly, Inferentially, presumptively, indirectly, eventually, circumstantially, inconclusively.
every now and then (adverb)
sometimes.
infrequently (adverb)
irregularly, seldom, at random, unusually, hardly, sporadically, infrequently, sparsely, uncommonly, rarely, oddly.
irregularly (adverb)
now and again, uncertainly.
now and then (adverb)
from time to time, at times, on occasion, every so often.
once in a while (adverb)
now and then.

n.

intermittent, spasmodic, every so often, (every) now and then/again, sporadic, occasional, infrequent. periodically, betimes, intermittently, sometimes, continue. usual, little, seldom. occasionally (noun)
from time to time, on occasion, now and again, at times, once in a while, now and then.

Other synonyms:

intermittently, infrequent, occasional, intermittent. spasmodic, betimes, sometimes, sporadic, periodically. little. from time to time
from time to time.
now and again
now and again.
once in a while
once in a while.
rarely
seldom.
Other relevant words:
hardly, every so often, betimes, on occasion, infrequent, irregularly, intermittently, little, sometimes, seldom, now and then, at times, periodically, once in a while, from time to time, now and again, at random, occasional.

Usage examples for occasionally

  1. While my Play goes on, I must permit him to come forward occasionally – The Complete Project Gutenberg Works of George Meredith by George Meredith
  2. Occasionally they are found farther from the hill. – Tobacco; Its History, Varieties, Culture, Manufacture and Commerce by E. R. Billings