on their best behavior
idiom
: exhibiting proper behavior
The children were all on their best behavior at the museum.
Examples of on their best behavior in a Sentence
Recent Examples on the Web
There's a slight risk of rain later this week, so drivers will have to be on their best behavior as the season begins.
—
Justin Gest, Newsweek, 11 Feb. 2025
Kang-hee, played by Lee Se-young, grew up in the motel where her father often forgot to pay the bills and the guests are rarely on their best behavior.
—Joan MacDonald, Forbes, 14 Jan. 2025
Snoop Dogg's grandkids are going to have to be on their best behavior this holiday season!
—Hannah Sacks, People.com, 6 Dec. 2024
There’s cordiality and decorum at these events; anyone can be on their best behavior for a day or so.
—Julia Cho, New York Times, 21 May 2024
See all Example Sentences for on their best behavior 
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Justin Gest, Newsweek, 11 Feb. 2025
Kang-hee, played by Lee Se-young, grew up in the motel where her father often forgot to pay the bills and the guests are rarely on their best behavior.
—Joan MacDonald, Forbes, 14 Jan. 2025
Snoop Dogg's grandkids are going to have to be on their best behavior this holiday season!
—Hannah Sacks, People.com, 6 Dec. 2024
There’s cordiality and decorum at these events; anyone can be on their best behavior for a day or so.
—Julia Cho, New York Times, 21 May 2024
See all Example Sentences for on their best behavior
Dictionary Entries Near on their best behavior
Cite this Entry
“On their best behavior.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/on%20their%20best%20behavior. Accessed 22 Feb. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share