in·fir·mi·ty 
/ɪnˈfɚməti/ noun
plural in·fir·mi·ties /ɪnˈfɚməti/ noun 1 [noncount] : the quality or state of being weak or ill especially because of old age
▪ In recent years she has had to reduce her schedule because of age and infirmity. 2 [count] : a disease or illness that usually lasts for a long time
▪ the infirmities of old age
▪ In recent years she has had to reduce her schedule because of age and infirmity.
▪ the infirmities of old age
