The mental and physical deterioration associated with aging. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "senility" in a sentence
"Many people greatly misuse the word senility when wanting to convey the idea that the aged individual that they are referring to has memory loss, confusion etc., when the appropriate word is dementia."
"Conversely, much not all—there are biological factors involved of what we call senility is a fatal end-stage form of psychological and spiritual immaturity."
"Ah well as Forrest might say senility is as senility does."