The Collaborative International Dictionary of English v.0.48:

Humped \Humped\, a.
   Having a hump, as the back.
   [1913 Webster]

WordNet (r) 3.0 (2006):

humped
    adj 1: characteristic of or suffering from kyphosis, an
           abnormality of the vertebral column [syn: crookback,
           crookbacked, humped, humpbacked, hunchbacked,
           gibbous, kyphotic]