senile

American  

[see-nahyl, -nil, sen-ahyl] / ˈsi naɪl, -nɪl, ˈsɛn aɪl /

adjective

1. showing a decline or deterioration of physical strength or mental functioning, especially short-term memory and alertness, as a result of old age or disease.

2. of or belonging to old age or aged persons; gerontological; geriatric.

3. Physical Geography. (of topographical features) having been reduced by erosion to a featureless plain that stands everywhere at base level.

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noun

1. a senile person.

senile British  

/ ˈsiːnaɪl, sɪˈnɪlɪtɪ /

adjective

1. of, relating to, or characteristic of old age

2. mentally or physically weak or infirm on account of old age

3. (of land forms or rivers) at an advanced stage in the cycle of erosion See old

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Other Word Forms

• senilely
  adverb
• senility
  noun
• unsenile
  adjective

Etymology

Origin of senile

First recorded in 1655–65; from Latin senīlis “old,” from sen(ex) “old man” ( cf. senior) + -īlis -ile

Explanation

The word senile describes a person who is experiencing dementia brought about by old age — in other words, someone showing signs of senility. Senile can refer to a loss of physical abilities in old age, but it usually refers to decreased memory and mental faculties. Getting senile is a very serious condition, as an older person might have trouble remembering who their own children are. Many people in nursing homes are senile, because their families aren't able to provide proper care. Of course, people forget things at every age. If you're 10 or 40 and have a bad memory, you're not going senile.

Example Sentences

I asked him about that moment just after it happened, and had asked him whether the president was senile the day before.

From BBC • Jul. 22, 2024

Especially if a person seems to go senile very quickly, check their vitamin B12!

From Seattle Times • Apr. 17, 2024

She has no choice but to carry this pregnancy to term, surrounded by jealous novitiates, senile nuns, controlling male leadership and a secret sect of the sisterhood who wear crimson shrouds over their faces.

From Los Angeles Times • Mar. 20, 2024

She entered hospice care in late December 2022 with senile degeneration of the brain and was treated with the anxiety drug lorazepam and morphine, a painkiller, according to the report.

From New York Times • Feb. 5, 2023

By this time the truck was little more than four wheels and an engine and the engine was so crotchety and sullen and senile that it required expert care and consideration.

From "Cannery Row" by John Steinbeck