senile

adjective

se·​nile ˈsē-ˌnī(-ə)l 

also

ˈse- 

1

: of, relating to, exhibiting, or characteristic of old age

senile osteoporosis

especially, sometimes disparaging + offensive : exhibiting a decline of cognitive abilities (such as memory) associated with old age

Note: This use of senile is now typically avoided in medical contexts and may be considered offensive in general contexts.

2

: approaching the end of a geologic cycle of erosion

Located in a region known for its erosional history by river Ganga and Yamuna, its senile topography yields pulses, cereals and millets, oilseeds and fodder crops.

—Shruthi Mohan

senilely

ˈsē-ˌnī(-ə)l-lē 

 also  ˈse-

adverb

Examples of senile in a Sentence

a senile man in his eighties

Her mother is becoming senile.

Recent Examples on the Web

The kids can’t spell and the world leaders are senile. —Literary Hub, 21 Oct. 2025

Back on the domestic front, Jeanine has reason to believe that her husband, Paul (Mark O’Brien), is having an affair with her senile mother’s caregiver. —Michael Rechtshaffen, The Hollywood Reporter, 9 Sep. 2023

Don Quixote himself is too often a senile dodderer; Daniel Rubin was creaky in body but youthfully quixotic in spirit. —Jeffrey Gantz, BostonGlobe.com, 17 Mar. 2023

But Benjamin Smith, a professor of Latin American history at the University of Warwick in Britain, said the tweet could further fuel ongoing rumors that López Obrador, 69, is senile or otherwise unfit to govern. —Bryan Pietsch, Washington Post, 25 Feb. 2023

Word History

Etymology

Latin senilis, from sen-, senex old, old man

First Known Use

1595, in the meaning defined at sense 1

Phrases Containing senile

• senile dementia

Rhymes for senile

• argyle
• awhile
• beguile
• compile
• condyle
• defile
• erstwhile
• exile
• freestyle
• gentile
• hairstyle
• lifestyle

Kids Definition

senile

adjective

se·​nile ˈsēn-ˌīl 

 also  ˈsen-

: of, relating to, or characteristic of old age

senile weakness

especially : showing a decline in mental abilities usually associated with old age

Etymology

from Latin senilis "showing the features of old age," from sen-, senex "old" — related to senior

Medical Definition

senile

adjective

se·​nile

ˈsēn-ˌīl also ˈsen-

1

: of, relating to, exhibiting, or characteristic of old age

senile osteoporosis

especially, sometimes disparaging + offensive : exhibiting a decline of cognitive abilities (as memory) associated with old age

Note: Due to its negative connotations, use of senile relating to cognitive decline is now typically avoided in medical contexts and may be considered offensive in general contexts.

2

of a cell : marked by senescence (see senescence sense 2)

As people accumulate exhausted T-cells, an adverse consequence is that the senile cells emit pro-inflammatory cytokines …

—William Faloon, Life Extension