まい (mai): Will not; probably not
～まい (mai)
Meaning
Will not; probably not
Formation and usage
V dictionary + まい; ichidan／する also stem + まい
Notation: N = noun; V dictionary = dictionary-form verb; V stem = the stem before ます; plain clause = plain-form clause; negative stem = the form before ない. Follow the attachment shown above.
Explanation
Can express either negative intention or a negative conjecture, depending on subject and context.
Examples
二度とうそをつくまいと決めた。
I decided that I would never tell a lie again.
二度と秘密を漏らすまいと決めた。
I decided that I would never reveal the secret again.
二度と約束を破るまいと決めた。
I decided that I would never break a promise again.
二度と仲間を裏切るまいと決めた。
I decided that I would never betray one's teammates again.
二度と責任を放棄するまいと決めた。
I decided that I would never abandon one's responsibilities again.
How related patterns differ
まい can express negative intention or conjecture; まいか can convey uncertainty. ものやら wonders about something hard to know. というわけではない rejects an interpretation, も何も rejects a premise, and と思いきや introduces a surprising reversal.