monkey business
US /ˈmʌŋ.ki ˈbɪz.nɪs/
UK /ˈmʌŋ.ki ˈbɪz.nɪs/

1.
bêtises, manigances, farces
silly, dishonest, or mischievous behavior
:
•
Stop all that monkey business and get to work!
Arrête toutes ces bêtises et mets-toi au travail !
•
The teacher suspected some monkey business was going on during the exam.
Le professeur soupçonnait des manigances pendant l'examen.