(a) literal of a person, an animal, a chair, etc.; (b) not bending the back for work, idle; (c) not given to lounging, energetic.

having a back shaped like a lute.

Of an animal or person: having an arched or rounded back.

Having a humped or crooked back; hunched, esp. in the names of fishes; cf. humpback, n. adj. Also transferred.

(a) slang long-backed (obsolete); (b) mackerel-backed sky: = mackerel sky n. at mackerel, n.1 compounds 2.