senility

noun

se·​nil·​i·​ty si-ˈni-lə-tē 

 also  se-

sometimes offensive

: the quality or state of being senile : the physical and mental decline associated with old age

especially : the deterioration of cognitive functioning associated with old age

Note: Senility is now typically avoided in medical contexts and may be considered offensive in general contexts because of its negative implication that cognitive decline is part of the normal aging process. Dementia is usually considered the appropriate term to use when describing the serious progressive cognitive decline that most commonly affects older adults.

Synonyms of senility

• feebleness
• dotage

Examples of senility in a Sentence

with his increasing senility, Granddad is beginning to have more and more senior moments

Recent Examples on the Web

After the muddle of Kamala Harris and the senility of Joe Biden, Democrats need substantive and sophisticated leaders primed for traditional and new media alike. —Harpers Magazine, 19 Sep. 2025

And their patriarch, battling the cruel advance of senility. —Lauren Huff, EW.com, 11 July 2025

As populations’ median ages continue to rise — and the future looks increasingly hazardous for all age groups — more movies are touching on senility, dementia, elder abuse and other topics that not long ago rarely got any screen airing. —Dennis Harvey, Variety, 11 Mar. 2025

Salles doesn’t clarify his viewpoint until the end, when Eunice ages into senility. —Armond White, National Review, 7 Feb. 2025

Word History

First Known Use

1652, in the meaning defined above

Rhymes for senility

• ability
• agility
• civility
• debility
• docility
• ductility
• facility
• fertility
• fragility
• futility
• gentility
• hostility

Kids Definition

senility

noun

se·​nil·​i·​ty si-ˈnil-ət-ē 

: the quality or state of being senile

especially : a decline in mental abilities that is associated with old age

Medical Definition

senility

noun

se·​nil·​i·​ty

si-ˈnil-ət-ē also se-

plural senilities

: the quality or state of being senile : the physical and mental decline associated with old age

especially : the deterioration of cognitive functioning associated with old age

Note: Due to its negative implication that cognitive decline is part of the normal aging process, use of the term senility is now typically avoided in medical contexts and may be considered offensive in general contexts. Dementia is usually considered the appropriate term to use when describing the serious progressive cognitive decline that most commonly affects older adults.