be on your best behaviour

Meaning

1. Oxford100% of films

   to behave in the most polite way you can

   Now, remember. Be on your best behaviour.

In the movies · 2

• Now, remember. Be on your best behaviour.Mary Poppins1964
• All right, look, yous three, yous three, I want yous on your best behaviour.This Is England2007
• Right? Your fucking best behaviour.This Is England2007

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