infirmin‧firm /ɪnˈfɜːm $ -ɜːrm/ adjective 
- He was too infirm to hold a steady job.
- She lives with her grandmother who is elderly and infirm.
- The "Meals on Wheels' service delivers food to the old and infirm.
not physically strong► weak not physically strong, sometimes because you are ill: · Tom’s had flu and he’s still feeling weak.· The doctors said she was too weak to have an operation.· He suffered constantly from a weak chest.
► frail weak and thin, especially because you are old: · a frail 85-year-old lady· My grandfather’s becoming quite frail now.
► shaky feeling weak in your legs and only able to walk slowly and unsteadily: · When I came out of hospital I was a bit shaky for a while.
► puny especially disapproving small, thin, and looking very weak: · his puny white arms· He was a puny little boy who was often bullied at school.
► feeble especially written weak and unable to do much because you are very ill, very old or very young: · For a week she was too feeble to get out of bed.· a tiny, feeble baby
► delicate weak and often becoming ill easily: · a delicate child· She had rather a delicate constitution (=her body easily became ill).
► infirm formal weak or ill for a long time, especially because you are old: · a residential home for people who are elderly and infirm· There are special facilities for wheelchair users and infirm guests.
► malnourished formal weak or ill because you have not had enough good food to eat: · Half a million people there are severely malnourished.· The organization provides emergency feeding for malnourished children.
when someone is often ill► sickly a sickly child is often ill: · He was a sickly child with a bad chest and a permanent cough.· Louise, who was often sickly, couldn't join in the other children's games.
► delicate formal unhealthy and weak and likely to become ill easily: · Clare was more active than her brother, who had always been a delicate child.· Mr Humphreys' wife was delicate - the doctor was called in once or twice a week.
► in poor health fairly ill all the time or over a long period of time, and generally not strong and healthy: · When he left Trinidad he was already over 60, frail, and in poor health.
► infirm formal not healthy or strong, especially because of old age: · She lives with her grandmother who is elderly and infirm.the infirm (=people who are infirm): · The "Meals on Wheels' service delivers food to the old and infirm.
► prone to something likely to become ill or to get a particular illness: · As a child she had always been prone to allergies.· The disease had left her weak and prone to all kinds of infections.
nounfirmnessinfirmitythe infirmadjectivefirminfirmadverbfirmly
Her grandmother is elderly and infirm.► see thesaurus at weak2the infirm people who are weak or ill for a long time, especially because they are old: