definition of
[telltale]

[1] #1 telltale s. [revealing, telling] disclosing unintentionally; "a telling smile"; "a telltale panel of lights"; "a telltale patch of oil on the water marked where the boat went down". wn

[2] #2 telltale n. [tattletale, tattler, taleteller, talebearer, blabbermouth] someone who gossips indiscreetly. wn