でなければ

expression

if not; without; otherwise; or else

Conditional expression meaning 'if it is not the case' or 'unless'. Used to state a necessary condition or a negative alternative. Often appears at the beginning of a clause.

• 急いそがなければならない。でなければ遅ち刻こくする。

  We have to hurry. Otherwise we'll be late.

• 雨あめでなければ、ピクニックに行いきます。

  If it doesn't rain, we'll go on a picnic.