The Collaborative International Dictionary
Truth-teller
Truth-teller \Truth"-tell`er\, n. One who tells the truth.
Truth-teller was our England's Alfred named.
--Tennyson.
Usage examples of "truth-teller".
My doctor's eyes told me that this was not a blindness from birth, but one more recent and gradual: her skin, the truth-teller, was mottled and scarred from recurrent infection, the nails pale, suggesting a circulatory failure of the small vessels, most likely severe diabetes.
Back when the world's most famous whistle-blower produced tapes proving the president of the United States had committed a slew of felonies, the Left was somewhat muted in its enthusiasm for female truth-tellers.