Na-adjective (keiyodoshi), Noun
polite; courteous; civil
漢字を書くときは点やはらいに気をつけて、なるべく早くていねいに書きましょう。When drawing kanji be careful of dots and sweeps, write as carefully and quickly as possible. careful; close; thorough; conscientious
Also written 叮嚀【ていねい】