Definition of "telltale" []

• One who informs on another; a talebearer. (noun)
• Something that indicates or reveals information; a sign. (noun)
• Any of various devices that indicate or register information, especially: (noun)
• A time clock. (noun)
• Nautical One of the brightly colored lengths of yarn or ribbon attached to the shrouds, stays, or sails of a sailboat, serving to indicate wind direction relative to the boat's motion. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "But state bushfire chief Phil Koperberg said commanders were watching up to 30 suspects for certain telltale signs."
• "Sometimes seeing someone you have a crush on results in telltale physiological signs."
• "The "Dra" bit refers to a telltale sign of viral infection—double-stranded RNA molecules—while the "co" bit concerns the mechanism by which a cell commits suicide if so infected."