ultraviolet vs invisible

ultraviolet is a noun but invisible is not a noun.

Word	Noun	Adjective	Verb	Adverb
ultraviolet	Yes	Yes	No	No
invisible	No	Yes	No	No

ultraviolet (noun)	invisible (noun)
radiation lying in the ultraviolet range; wave lengths shorter than light but longer than X rays

ultraviolet (adjective)	invisible (adjective)
having or employing wavelengths shorter than light but longer than X-rays; lying outside the visible spectrum at its violet end	impossible or nearly impossible to see; imperceptible by the eye
	not prominent or readily noticeable