on one's best behavior

Also, on one's good behavior. Very polite, as in Mother told the children to be on their best behavior during Grandma's visit, or The whole staff were on their good behavior while the client inspected the premises. [Late 1600s]

Common Names:

Name	Pronounced	Usage
Dipali	-	Indian, Hindi, Marathi
Ryuu	ṙyoo:	Japanese
Gayla	GAY-lə	English
Usha	-	Hinduism, Indian, Kannada, Tamil, Telugu, Malayalam, Hindi, Marathi, Nepali
Kenyon	-	English
Iro	-	Greek