The noun dotage describes the mental decline that many elderly people eventually experience. Those in their dotage sometimes act silly or forgetful.
The first syllable in dotage rhymes with go: "DOE-tage." The verb dote means "to be silly" and also "to be infatuated," both of which can at times describe those in their dotage (including a renewed interest in romance that many may not have experienced since they were giddy teenagers, in love for the first time).
