humpbacked vs crookback

humpbacked is not a noun while crookback is a noun.

Word	Noun	Adjective	Verb	Adverb
humpbacked	No	Yes	No	No
crookback	Yes	Yes	No	No

As adjectives, humpbacked and crookback are synonyms defined as:

humpbacked and crookback: characteristic of or suffering from kyphosis, an abnormality of the vertebral column

Other synonyms of humpbacked include crookbacked, gibbous, humped, hunchbacked, kyphotic.

humpbacked (noun)	crookback (noun)
	a person whose back is hunched because of abnormal curvature of the upper spine

humpbacked (adjective)	crookback (adjective)
characteristic of or suffering from kyphosis, an abnormality of the vertebral column	characteristic of or suffering from kyphosis, an abnormality of the vertebral column