We found one dictionary that defines the word be on your best behavior:

General (1 matching dictionary)

▸ Words similar to be on your best behavior ▸ Usage examples for be on your best behavior ▸ Idioms related to be on your best behavior ▸ Wikipedia articles (New!) ▸ Words that often appear near be on your best behavior ▸ Rhymes of be on your best behavior ▸ Invented words related to be on your best behavior