ちまうto do something completely

祖父(そふ)：「昔(むかし)のことは忘(わす)れちまったよ。」

Grandfather: "I've completely forgotten about the past." {to do something completely}

泥棒(どろぼう)：「証拠(しょうこ)になるような物(もの)は捨(す)てちまえ！」

Thief: "Get rid of anything that could serve as evidence, completely!" {to do something completely}

僕(ぼく)は過去(かこ)に友達(ともだち)の物(もの)を取(と)っちまったことを後悔(こうかい)している。

I regret having completely taken my friend's belongings in the past. {to do something completely}

母(はは)：「あとちょっとしか残(のこ)ってないじゃないか。食(た)べちまいなさい。」

Mother: "There's only a little left, isn't there? Eat it all up." {to do something completely}

先生(せんせい)：「生徒(せいと)が窃盗(せっとう)をしたとは…困(こま)っちまうな。どうすれば良(よ)いのだ…。」

Teacher: "A student committing theft... It's quite troubling. What should be done..." {to do something completely}