once in a while
idiomOccasionally; sometimes.
- 01
all at once
Unexpectedly; without warning; all of a sudden.
- 02
for this once
On this particular occasion, to make an exception
- 03
once again
Again, once more, one more time.
- 04
once and for all
Conclusively, finally, permanently.
- 05
once in a blue moon
Very rarely; very infrequently.
- 06
once in a purple moon
Extremely rarely; almost never.
- 07
once or twice
A small, indefinite number of times.