Meaning : Sporadically and infrequently.
Example :
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.
Synonyms : at times, from time to time, now and again, now and then, occasionally, on occasion
Once in a while ka meaning, vilom shabd, paryayvachi aur samanarthi shabd in Marathi. Once in a while ka matlab kya hota hai?