みっちりseverely, strictly, fully, earnestly, diligently

お金(かね)を貯(た)めるためにみっちり働(はたら)くぞ！

I'm going to work diligently to save money! {severely, strictly, fully, earnestly, diligently}

大会(たいかい)までみっちりと練習(れんしゅう)をするつもりです。

I plan to practice diligently until the tournament. {severely, strictly, fully, earnestly, diligently}

みっちりと腕(うで)を磨(みが)いた弟子(でし)に師匠(ししょう)が感激(かんげき)しました。

The master was impressed by the disciple who diligently honed his skills. {severely, strictly, fully, earnestly, diligently}

試合(しあい)に向(む)けてみっちり練習(れんしゅう)したのに、試合(しあい)で負(ま)けてしまった。

Despite practicing diligently for the match, I ended up losing in the game. {severely, strictly, fully, earnestly, diligently}

夏休(なつやす)みに英語(えいご)をみっちり勉強(べんきょう)したからか、英語(えいご)の成績(せいせき)が上(あ)がりました。

My English grades improved because I studied English diligently during summer vacation. {severely, strictly, fully, earnestly, diligently}