Given to moralising in a pompous or affected manner.
Late Middle English: from Latin sententiosus, from sententia ‘opinion’ (see sentence). The original sense was ‘full of meaning or wisdom’, later becoming depreciatory.
“He’s a sententious old man and I’m not listening any more!”
The last stage of life; old age.
Senectitude comes from the Medieval Latin noun senectitūdō meaning “old age,” which in turn comes from Classical Latin senectūs, a derivative of the noun senex meaning “old man.” Senectitude entered English in the late 1700s, more precisely, in 1796 in Jonathan Swift’s Gulliver’s Travels