entry
infirmity
/ɪnˈfɝːmət̬i/Weakness, illness, or moral frailty, especially age-related
From Latin infirm (Weak).
Word Ancestry
The word begins with a small verbal shove: Latin in- means “not,” placed before firmus, “strong” or “steady.” Firmus is related to the same ancient idea of holding something securely, the reconstructed PIE root *dher-, which also lurks behind words such as firm and firmament—the “solid” sky imagined as a supporting structure. By the late fourteenth century, English infirm could describe things that were unsound; by about 1600, it was being used especially for people who were weak or unhealthy. Add the abstract-noun suffix -ity, and the result names not merely a frail person but the condition itself: infirmity. The word can describe a failing body, particularly in old age, but it can also point to a moral weakness—a reminder that “not firm” once applied to character as readily as to knees.
The Story
The word begins with a small verbal shove: Latin in- means “not,” placed before firmus, “strong” or “steady.” Firmus is related to the same ancient idea of holding something securely, the reconstructed PIE root *dher-, which also lurks behind words such as firm and firmament—the “solid” sky imagined as a supporting structure. By the late fourteenth century, English infirm could describe things that were unsound; by about 1600, it was being used especially for people who were weak or unhealthy. Add the abstract-noun suffix -ity, and the result names not merely a frail person but the condition itself: infirmity. The word can describe a failing body, particularly in old age, but it can also point to a moral weakness—a reminder that “not firm” once applied to character as readily as to knees.
Kin & Kindred
From 'infirm'·Weak, frail, unhealthy, or not strong
Derived Terms
English words from this root
From '-ity'·State, condition, or quality
Derived Terms
English words from this root
Sources
Etymonline
Free Dictionary
Urban Dictionary
Wikipedia
Wiktionary