stiff vs immobile

stiff is a noun but immobile is not a noun.

Word	Noun	Adjective	Verb	Adverb
stiff	Yes	Yes	No	Yes
immobile	No	Yes	No	No

stiff (noun)	immobile (noun)
the dead body of a human being
an ordinary man

stiff (adjective)	immobile (adjective)
having a strong physiological or chemical effect	not capable of movement or of being moved
rigidly formal	securely fixed in place
not moving or operating freely
very drunk
marked by firm determination or resolution; not shakable
strong, vigorous
incapable of or resistant to bending

stiff (adverb)	immobile (adverb)
in a stiff manner
to a great degree