あっという間
Expression- 1an instant ; a split second ; no time at all ; time of an "ah!" Translated by Jiyomi
Other writings and readings
あっと言う間アッという間アッと言う間あっとゆう間アッとゆう間あっとゆー間あっとゆうまあっとゆーま
expressions (phrases, clauses, etc.) · noun (common) (futsuumeishi)
JMdict entry 2208410 · frequency rank 50. Source and licence.