on (one's) good behavior

Being very polite or exercising exceptionally good manners. Primarily heard in US. Now, you kids must be on your good behavior for your Auntie this weekend! Good morning, class. I hope everyone was on their good behavior for the substitute teacher yesterday.

Common Names:

Name	Pronounced	Usage
Abdur-Rashid	-	Arabic
Prisca	PRIS-kə (English)	Biblical, Dutch, Ancient Roman, Biblical Latin
Waramunt	-	Ancient Germanic
Gibbs	[gibz]
Alex	AL-əks (English), AH-ləks (Dutch)	English, Dutch, German, French, Portuguese, Italian, Romanian, Swedish, Norwegian, Danish, Icelandic
Chalchiuhticue	-	Aztec and Toltec Mythology