swayback vs swaybacked

swayback and swaybacked both are adjectives.

Word	Noun	Adjective	Verb	Adverb
swayback	No	Yes	No	No
swaybacked	No	Yes	No	No

As adjectives, swayback and swaybacked are synonyms defined as:

swayback and swaybacked: having abnormal sagging of the spine (especially in horses)

Other synonyms of swayback include dipped, lordotic.

swayback (adjective)	swaybacked (adjective)
having abnormal sagging of the spine (especially in horses)	having abnormal sagging of the spine (especially in horses)