blind vs sightless

blind is a noun but sightless is not a noun.

Word	Noun	Adjective	Verb	Adverb
blind	Yes	Yes	Yes	No
sightless	No	Yes	No	No

blind (noun)	sightless (noun)
a protective covering that keeps things out or hinders sight
a hiding place sometimes used by hunters (especially duck hunters)
something intended to misrepresent the true nature of an activity
people who have severe visual impairments, considered as a group

blind (adjective)	sightless (adjective)
unable to see	lacking sight
not based on reason or evidence
unable or unwilling to perceive or understand

blind (verb)	sightless (verb)
make dim by comparison or conceal
make blind by putting the eyes out
render unable to see