tell on

US /tel ɑːn/
UK /tel ɑːn/
"tell on" picture
1.

denunciare, fare la spia

to inform an authority figure about someone's bad behavior

:
If you don't stop, I'm going to tell on you.
Se non smetti, ti denuncerò.
The little boy decided not to tell on his sister.
Il bambino decise di non denunciare sua sorella.