Revealing or betraying something (8)

I believe the answer is:

telltale

(Other definitions for telltale that I've seen before include "Betraying" , "One spreads other people's secrets" , "Blabbing person" , "Person who blabs, or something revealing" , "Informer - monitoring device" .)

I've seen this clue in The Mirror.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.