conjunction
if not so; otherwise
Archaic or highly formal literary conjunction meaning 'if it is not so' or 'otherwise'. In modern Japanese, そうでなければ or さもなければ are more common.
しからずんば、この計画は失敗に終わるだろう。
If not so, this plan will end in failure.
Derived from classical Japanese 然らず (shikarazu, 'it is not so') + ば (ba, conditional particle). The form is now archaic and rarely used outside of literary or formal contexts.