be on your best behaviour
US /bi ɑn yʊər bɛst bɪˈheɪvjər/
UK /bi ɑn yʊər bɛst bɪˈheɪvjər/
1.
se tenir à carreau, bien se comporter
to act in the most polite and proper way possible, especially in a situation where you want to make a good impression
:
•
When you meet my parents, I expect you to be on your best behaviour.
Quand tu rencontreras mes parents, j'attends de toi que tu te tiennes à carreau.
•
The children were told to be on their best behaviour during the school trip.
On a dit aux enfants de se tenir à carreau pendant la sortie scolaire.