まない
sumanai

i-Adjective

1. inexcusable; unjustifiable; unpardonable

Usually Written in Kana
i-Adjective

2. sorry; remorseful; apologetic; conscience-stricken; contrite

Usually Written in Kana
たせてすまなかったな。
matasete sumanakattana.
I am sorry to have kept you waiting.
Interjection

3. excuse me; (I'm) sorry; thank you

Usually Written in Kana
Related to すみません
すまないが いま ぼく、手 がいっぱいなのだ。
sumanaiga ima boku tega ippaina noda.
Excuse me, but I'm tied up now.