gibbous vs crookback

gibbous is not a noun while crookback is a noun.

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

As adjectives, gibbous and crookback are synonyms defined as:

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

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

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

gibbous (adjective)	crookback (adjective)
(used of the moon) more than half full	characteristic of or suffering from kyphosis, an abnormality of the vertebral column
characteristic of or suffering from kyphosis, an abnormality of the vertebral column