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
At the beginning of a relationship, everyone is usually on their best behavior, which can make this valuable green flag hard to spot early on.
—
Baya Voce, CNBC, 27 Nov. 2025
And then there were my bohemian artist parents, a pair of bomb throwers even on their best behavior.
—Daisy Rockwell, Vogue, 27 Nov. 2025
When Bell was younger, as the holidays approached, her parents would set out a toy Elf, who watched, listened and reported back to Santa Claus — at least, that's what Bell and her siblings were told as a way to keep them on their best behavior.
—Meredith Wilshere, PEOPLE, 22 Nov. 2025
Everyone’s coming into them on their best behavior and even feuds are parked at the entrance for a while.
—Lizzie Lanuza, StyleCaster, 20 Nov. 2025
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.
Baya Voce, CNBC, 27 Nov. 2025
And then there were my bohemian artist parents, a pair of bomb throwers even on their best behavior.
—Daisy Rockwell, Vogue, 27 Nov. 2025
When Bell was younger, as the holidays approached, her parents would set out a toy Elf, who watched, listened and reported back to Santa Claus — at least, that's what Bell and her siblings were told as a way to keep them on their best behavior.
—Meredith Wilshere, PEOPLE, 22 Nov. 2025
Everyone’s coming into them on their best behavior and even feuds are parked at the entrance for a while.
—Lizzie Lanuza, StyleCaster, 20 Nov. 2025
See All Example Sentences for 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 24 Dec. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share