from Latin protervus forward, bold, pert, wanton, impudent
Etymology of Latin protervus doubtful. Walde suggests after Fröhde pro-pterguos, from pro- + cogn. of Greek πτέρυξ wing.
(From A New English Dictionary on Historical Principles, James Murray)
1382 - Wyclif - see below from E-NED
From: Satirical Poems of the Time of the Reformation,
Edited by James Cranstoun, Volume I, 1891
Ane Exhortation derect to my Lord Regent and to the
Rest of the Lordis accomplisis