dote (v.)

c. 1200, "behave irrationally, do foolish things, be silly or deranged," also "be feeble-minded from age," probably from an unrecorded Old English word akin to Middle Low German and Middle Dutch doten "be foolish, be out of one's mind," which is of unknown origin. Also in Middle English "to decay, deteriorate," in reference to rotten timber, etc. (mid-15c.). There was a noun dote "fool, simpleton, senile man" (mid-12c.), but Middle English Dictionary considers this to be from the verb. Related: Doted; dotes; doting.