hy ‧ po ‧ chon ‧ dri ‧ a /ˌhaɪpəˈkɒndriə $ -ˈkɑːn-/ BrE AmE noun [uncountable]
[ Date: 1500-1600 ; Language: Late Latin ; Origin: (plural), 'parts of the body just below the chest' (which was thought to be where hypochondria came from), from Greek , 'parts below the central bone in the chest' , from hypo- ( ⇨ ↑ hypo- ) + chondros 'cartilage' ]
when someone continuously worries that there is something wrong with their health, even when they are not ill