WordReference Random House Unabridged Dictionary of American English © 2026
se•nil•i•ty
(si nil′i tē),USA pronunciation n.
WordReference Random House Learner's Dictionary of American English © 2026- Pathologythe state of being senile, esp. the weakness or mental infirmity of old age.
- senile + -ity 1770–80
se•nile /ˈsinaɪl, ˈsɛnaɪl/USA pronunciation
adj.
WordReference Random House Unabridged Dictionary of American English © 2026- showing a decline of physical strength or mental functioning as a result of old age or disease.
se•nile
(sē′nīl, -nil, sen′īl),USA pronunciation adj.
n.
- showing a decline or deterioration of physical strength or mental functioning, esp. short-term memory and alertness, as a result of old age or disease.
- of or belonging to old age or aged persons;
gerontological;
geriatric. - Geography, Place Names[Physical Geog.](of topographical features) having been reduced by erosion to a featureless plain that stands everywhere at base level. Cf. peneplain.
n.
- a senile person.
- Latin senīlis old, equivalent. to sen(ex) old man (akin to senior) + -īlis -ile
- 1655–65
'senility' also found in these entries (note: many are not synonyms or translations):