간혹 + verb (간혹 있다); written ≈ spoken 가끔
occasionally, once in a while, now and then
Example
이런 실수는 간혹 일어나기도 합니다.
Mistakes like this do happen once in a while.
Word parts
간 interval+혹 perhaps
Literally 'in between, perhaps': something that turns up now and then.
Good to know
Common in the pattern 간혹 ~기도 하다, 'sometimes it also happens that ~'.
Related words