tell on

tell on (third-person singular simple present tells on, present participle telling on, simple past and past participle told on)

1. (usually childish) To inform on, to rat out; to tell a person in authority that someone else has done something wrong.

   My sister told on me when I didn't go to school.

   • Bible, 1 Sam. xxvii. 11

     Lest they should tell on us, saying, So did David.

2. To cause visible strain to.

   Years of drinking started to tell on his body.

• bewray

• Thesaurus:rat out