Age, Senility, Senescence and Dotage are comparable when they denote the period in one’s life when one is old in years and declining in body or mind or both.
Age is now usually replaced by old age except in literary use.
- age cannot wither her
—Shak.y - age, I make light of it, fear not the sight of it
—Higginson
Senility adds to age the implication of decay, especially of mental decay.
- rheumy old man, crumpled together . . . his mind gone down the road to senility
—Roberts
Senescence designates the period or the process of the decline which results in senility or old age; it is in the life of the individual the antithesis of youth or adolescence.
Dotage, even more than senility, implies the childishness or mental decline of age and thus indirectly heightens the suggestion of extreme old age.
- old Daniel begins; he stops short—and his eye, through the lost look of dotage, is cunning and sly
—Wordsworth