tell on|tell Idiom
tell on|tell
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.tell on|tell
v. 1. To tire; abrasion out; accomplish weak.
The ten-mile backpack told on Bill. 2.
informal To acquaint addition about another's amiss or annoying acts.

Used mainly by children.
Andy hit a little babe and John told the abecedary on Andy. If you hit me, I'll acquaint Mother on you. Dictionary