Divulge secrets, as in Don't trust him; he's apt to tell tales. This expression was first recorded about 1350. A variant, tell tales out of school, first recorded in 1530, presumably alluded to schoolchildren gossiping but was soon broadened to revealing secret or private information. Both may be obsolescent.
Words nearby tell tales
How to use tell tales in a sentence
As far as I can tell, this magazine spent as much time making fun of French politicians as it did of Muslims or Islam.
Police, their representatives and supporters tell us, ensure our freedom of speech through our ability to protest.Politicians Only Love Journalists When They're Dead|Luke O’Neil|January 8, 2015|DAILY BEAST
“Jeffrey wanted me to tell you that you looked so pretty,” the female voice said into my disbelieving ear.
They were going to tell their story, consequences be damned.
And I tell Ollie, just look at me, because they just pulled out the pistolas.The Story Behind Lee Marvin’s Liberty Valance Smile|Robert Ward|January 3, 2015|DAILY BEAST
And to tell the truth, she couldn't help wishing he could see, so he could make the game livelier.The Tale of Grandfather Mole|Arthur Scott Bailey
Ages back—let musty geologists tell us how long ago—'twas a lake, larger than the Lake of Geneva.
Each day she resolved, "To-morrow I will tell Felipe;" and when to-morrow came, she put it off again.Ramona|Helen Hunt Jackson
He wanted to tell her that if she called her father, it would mean the end of everything for them, but he withheld this.The Homesteader|Oscar Micheaux
Monsieur,” growls the baron, “stone walls have ears, you say if only they had tongues; what tales these could tell!Checkmate|Joseph Sheridan Le Fanu