telltale: Meaning and Definition of

tell•tale

1. a person who heedlessly or maliciously reveals private or confidential matters; tattler; talebearer.
2. a thing serving to reveal or disclose something.
3. any of various indicating or registering devices, as a time clock.
4. a gauge on an organ for indicating the air pressure.
5. an indicator showing the position of a ship's rudder.
6. a row of strips hung over a track to warn train crew members on freight trains that a low bridge, tunnel, or the like is approaching.
7. (on a sailboat) a feather, string, or similar device, often attached to the port and starboard shrouds and to the backstay, to indicate the relative direction of the wind.
8. a narrow piece of metal across the front wall of a court, parallel to and extending 17 inches (43.2 cm) above the base: a ball striking this is an out.

1. that reveals or betrays what is not intended to be known: a telltale blush.
2. giving notice or warning of something, as a mechanical device.