tell on somebody phrasal verb informal (see also tell)
to tell someone in authority about something wrong that someone you know has done – used especially by children:
Please don’t tell on me – my parents will kill me if they find out!

[TahlilGaran] Dictionary of Contemporary English ▲

tell on
tell on (someone)
to give information about bad behavior to someone in authority.
None of his friends told on Louie, not even when he slipped live grasshoppers into a mailbox.

[TahlilGaran] English Idioms Dictionary ▲

tell on
to reveal the activities or wrongdoings of someone by telling others
The girl told on her brother for eating the cake.

[TahlilGaran] English Idioms Dictionary ▲

tell on
v.
1. To tire; wear out; make weak.
The ten-mile hike told on Bill.
2. informal To tell someone about another's wrong or naughty acts.
■ Used mainly by children.
Andy hit a little girl and John told the teacher on Andy.
If you hit me, I'll tell Mother on you.

[TahlilGaran] English Idioms Dictionary ▲

tell on someone
tell on (someone)
to give information about bad behavior to someone in authority.
None of his friends told on Louie, not even when he slipped live grasshoppers into a mailbox.

[TahlilGaran] English Idioms Dictionary ▲

tell on someone
to reveal the activities or wrongdoings of someone by telling others
The girl told on her brother for eating the cake.

[TahlilGaran] English Idioms Dictionary ▲