shameful, disgraceful, or unbecoming; something that looks bad or is inappropriate in public
そんなみっともない服装で来ないでください。
Please don't come dressed so disgracefully.
大人が子どもの前で泣きわめくのはみっともないと思う人もいる。
Some people think it's unbecoming for an adult to cry loudly in front of children.
酔って人に絡むのは本当にみっともない行為だ。
Getting drunk and bothering people is truly disgraceful behavior.
負けた後で言い訳ばかりするのはみっともない。
Making nothing but excuses after losing is unbecoming.