sitting vs unmoving

sitting is a noun but unmoving is not a noun.

Word	Noun	Adjective	Verb	Adverb
sitting	Yes	Yes	No	No
unmoving	No	Yes	No	No

sitting (noun)	unmoving (noun)
the act of assuming or maintaining a seated position
(photography) the act of assuming a certain position (as for a photograph or portrait)
a session as of a legislature or court
a meeting of spiritualists

sitting (adjective)	unmoving (adjective)
(of persons) having the torso erect and legs bent with the body supported on the buttocks	not arousing emotions
not moving and therefore easy to attack	not in motion