From Longman Dictionary of Contemporary Englishinfirmin‧firm /ɪnˈfɜːm $ -ɜːrm/ adjective 1 WEAKILLweak or ill for a long time, especially because you are old Her grandmother is elderly and infirm.► see thesaurus at weak2 → the infirm
Examples from the Corpus
infirm• She lives with her grandmother who is elderly and infirm.• The "Meals on Wheels' service delivers food to the old and infirm.• He was too infirm to hold a steady job. 