や否いなや

expression

as soon as; the minute (that); no sooner than

Used after the dictionary form of a verb to indicate that one action happens immediately after another. Often found in written or formal contexts.

• 彼かれは家いえに着つくや否いなや、電でん話わをかけた。

  As soon as he arrived home, he made a phone call.

• ベルが鳴なるや否いなや、生せい徒とたちは教きょう室しつを飛とび出だした。

  The minute the bell rang, the students rushed out of the classroom.

expression

whether or not

Rare and somewhat archaic use meaning 'whether or not'. Modern Japanese typically uses かどうか or 否か instead.

• 行いくや否いなや、まだ決きめていない。

  I haven't decided yet whether or not to go.