humpback

(noun) an abnormal backward curve to the vertebral column. Synonyms: kyphosis, hunchback.

(noun) a person whose back is hunched because of abnormal curvature of the upper spine. Synonyms: hunchback, crookback.

(noun) large whalebone whale with long flippers noted for arching or humping its back as it dives. Synonyms: humpback whale, Megaptera novaeangliae.