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
Polk County Sheriff Grady Judd said tourists are welcome in the county, but they are expected to be on their best behavior.
—
Elizabeth Pritchett, FOXNews.com, 5 Aug. 2025
The thousands of Floridians expected to march in the No Kings National Day of Defiance on Saturday had better be on their best behavior, warned Florida’s governor.
—Charles Rabin, Miami Herald, 13 June 2025
Major League Baseball arrived at the California state capital area Monday night, and everyone was on their best behavior trying to deal with a less-than-ideal situation for the Athletics.
—Barry M. Bloom, Sportico.com, 1 Apr. 2025
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
See All Example Sentences for on their best behavior
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Elizabeth Pritchett, FOXNews.com, 5 Aug. 2025
The thousands of Floridians expected to march in the No Kings National Day of Defiance on Saturday had better be on their best behavior, warned Florida’s governor.
—Charles Rabin, Miami Herald, 13 June 2025
Major League Baseball arrived at the California state capital area Monday night, and everyone was on their best behavior trying to deal with a less-than-ideal situation for the Athletics.
—Barry M. Bloom, Sportico.com, 1 Apr. 2025
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
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 19 Aug. 2025.
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