Denoting a task that can never be completed.
Late 16th century: from Latin Sisypheius (based on Greek Sisuphos: see Sisyphus)+ -an.
“It was a sisyphean task but she stuck at it.”
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