What does debility mean?
Debility is a noun referring to a state of physical or mental weakness, typically arising from illness, old age, malnutrition, or prolonged strain. It is a formal term, common in medical and clinical contexts — where phrases such as 'general debility' describe an overall loss of strength and vitality — but it also appears in literary and figurative uses to describe institutional or moral weakness. Unlike 'weakness', which can be momentary or specific (weakness in one arm), debility suggests a more pervasive and often lasting diminishment of vigour across body or mind. Its connotations are largely neutral and descriptive rather than judgemental: doctors may note a patient's debility without implying fault. Related words include 'debilitate' and 'debilitating', which are widely used in everyday English ('a debilitating illness'), making debility a useful root to know. The word traces back to Latin 'debilitas', from 'debilis' meaning weak.
A state of physical or mental weakness, especially one caused by illness, age, or exhaustion.
"The long convalescence was needed to restore strength lost through months of debility."
Often used in the fixed phrase 'general debility' in medical writing.
Weakness or lack of vigour in something figurative, such as an institution, economy, or character.
"Observers pointed to the debility of the once-powerful trade union movement."
The plural is uncommon; 'debility' is usually treated as uncountable when referring to a general state of weakness. The plural appears occasionally in literary or medical contexts to refer to distinct kinds or instances of weakness.
"Age brought with it a host of small debilities he had never expected."
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of debility
Debility comes from the Latin noun 'debilitas', derived from 'debilis', meaning 'weak' or 'lame', which combines the intensive prefix 'de-' with 'habilis', meaning 'able' or 'handy'. The word entered English in the early modern period, likely via French 'débilité', and has retained its core sense of weakness throughout its history. It shares this Latin root with the verb 'debilitate' and the adjective 'debilitating', both of which are common in modern English. Cognates appear across the Romance languages, including French 'débilité' and Italian 'debilità'.
How debility is actually used
Debility is a formal word, most often found in medical, clinical, or literary writing rather than everyday conversation. It carries a neutral-to-clinical connotation, describing a state of weakness without assigning blame. In older medical texts it was used very broadly for any weakened condition; today it tends to appear in phrases like 'general debility' or in discussions of ageing and chronic illness.
Easily confused with debility
'Inability' means the lack of ability or capacity to do something, while 'debility' refers to physical or mental weakness, not the absence of a specific skill.