まい
mai

Auxiliary Verb

1. probably isn't (doesn't, won't, etc.)

そうしたところできみにはなんもなるまい。
sōshita tokorode kiminiwa nanimo narumai.
You will gain nothing from doing that.
Auxiliary Verb

2. don't (doesn't) intend to; intend not to

相手あいてチームはラインをえさせまいとしたのです。
aitechiimuwa rain'o koesasemaito shita nodesu.
The other team tried to keep them from crossing the line.
Auxiliary Verb

3. must not; (when used in an imperative sentence) don't