(like) water off a duck's back
US /ˈwɔtər ɔf ə dʌks bæk/
UK /ˈwɔtər ɔf ə dʌks bæk/
1.
criticism or negative comments that have no effect on someone
:
•
He tried to insult her, but it was like water off a duck's back.
•
Criticism rolls off him like water off a duck's back.