Quand ton enfant lance son caca sur le mur

What does “bêtise” mean in French?

Une bêtise is built on bête (“stupid”, also “animal”) but it lands much more gently than that. Applied to a child it means mischief: something silly rather than wicked. Faire une bêtise is knocking the paint over; ne fais pas de bêtises is the line called after a kid leaving the room. It covers roughly the ground English gives to “that was naughty”.

Said of an adult the word hardens — faire une bêtise can mean acting recklessly — and dire des bêtises shifts to talking nonsense. In this clip a parent reaches for it after a toddler throws something at the wall: c’est une bêtise. Note how the reproach is framed impersonally — on ne jette pas..., “one doesn’t throw...” — which is how French adults often state a rule to a child rather than pointing at them with tu.