1715, from Fr.
effronterie, from
effronte "shameless," from O.Fr.
esfronte, probably from L.L.
effrontem (nom.
effrons) "barefaced," from L.
ex- "out" +
frontem (nom.
frons) "brow" (see
front). L.
frontus had a sense of "ability to blush," but the lit. sense of
effrontery has usually been taken to be "putting forth the forehead."