also: ざ
expression
if it is not ...; if it does not ...
Archaic or highly literary expression. Attaches to the -nai stem of a verb, usually paired with まい, especially as 〜ざあなるまい. Expresses a negative conditional: 'if it is not ...' or 'if it does not ...'. Not used in modern everyday speech.
See also: まい
「行かざあなるまい」は古い言い回しで、「行かなければならないだろう」という意味だ。
「行かざあなるまい」 is an old expression meaning 'I will probably have to go'.