To monish means to warn or advise someone.
Monish is a serious word. It means telling someone to be careful or to do something different.
Examples:
I will monish you to be careful.
The teacher will monish the students about the test.
He monished his friend not to go too fast.
The sign monished people not to swim in the river.
The wise old owl monished the young birds to be patient.
The police officer monished the drivers to slow down.