いざ知らず

Meanings

1. Expression

   I don't know about ... but; it may be possible for ... but

• 昔むかしならいざ知しらず、今いまはＦＡＸも、メールもある。

  I don't know about the past, but now we have faxes and emails.

• 彼かれならいざ知しらず、私わたしではその試験しけんには合格ごうかくできっこない。

  For him it may be possible, but I'd never pass the test.