dotard (n.)
old fool, senile idiot
Cym I.i.50 [First Gentleman to Second Gentleman, of Posthumus' role with the courtiers] to the graver / A child that guided dotards
MA V.i.59 [Leonato to Claudio] I speak not like a dotard nor a fool
TS V.i.96 [Baptista to Officer, of Vincentio] Away with the dotard
WT II.iii.74 [Leontes to Antigonus] Thou dotard