telltale sign

50 Moby Thesaurus words for "telltale sign":
      babbling, badge, banner, betrayal, blabbering, blabbing, character,
      characteristic, communication leak, dead giveaway, device,
      differentia, divulgation, divulgement, divulgence, divulging,
      earmark, evulgation, giveaway, hallmark, idiosyncrasy, image,
      index, indicant, indicator, indiscretion, insignia, keynote, leak,
      letting out, mark, measure, note, obvious clue, peculiarity,
      picture, property, representation, representative, seal, sigil,
      sign, signal, signature, stamp, sure sign, symptom, telltale,
      trait, unwitting disclosure