1. probably not; probably won't; probably doesn't; probably isn't
あんたにはわかるまい。You probably wouldn't understand.
2. intend not to; will not
僕はもう何も言うまい。I will not say anything more.
3. trying not to; attempting not to
as ～とする
4. whether you ... or not; whether one does ... or not
as ...（よ）うが...～が or ...（よ）うと...～と
あたしがいようがいまいが最後に勝つのはあなた。Whether I'm around or not, you're the one who wins in the end.
5. couldn't you?; won't you?; how about?
as ～か; indicates request or invitation
私の話を聞いてもらえまいか。Would you be willing to hear me out?
6. it's not as if ..., so; it's not like; it's not as though
as（では／でも）ある～し
お嬢様でもあるまいし。It's not like you're some pampered young lady.
7. would surely not ... (if); would never ... (and yet)
as（ある）～に; indicates counterfactuality
彼がいれば、こんなことにはなるまいに。If he were here, things would never have come to this.
8. surely not; there's no way that
as（では／でも）ある～に; indicates reproach; oft. at sentence end
子供でもあるまいに、何を泣いているの。You're not a child, so what are you crying for?
9. must not; don't; shall not
indicates prohibition; oft. as ～ぞ