Dense, thorough, or intensive (e.g., training, study); done with little slack and with careful, earnest effort.
試験前はみっちり復習しておいたほうがいい。
It's better to review thoroughly before the exam.
新人は先輩にみっちり指導されていた。
The new employee was given intensive instruction by a senior colleague.
時間がないのでみっちり詰めて打ち合わせをした。
We had a tightly scheduled meeting because there wasn't much time.
Tightly packed or compact; closely packed with little or no gaps.
箱の中にみっちり洋服が詰まっていた。
Clothes were packed tightly inside the box.
スケジュールがみっちりで休む時間もない。
My schedule is packed; there's not even time to rest.
彼のノートは細かい字でみっちり書かれている。
His notebook is filled densely with small handwriting.