invalidity  
noun [ U ] uk/ˌɪn.vəˈlɪd.ə.ti/ us/ˌɪn.vəˈlɪd.ə.t̬i/
  (NOT OFFICIAL)     
  无效,不合法
the condition of not being legally or officially acceptable
   (ILLNESS)     
 病弱(而不能工作或照顾自己)
the condition of being too ill to work or care for yourself