dye vs fast dye

dye is a noun but fast dye is not a noun.

Word	Noun	Adjective	Verb	Adverb
dye	Yes	No	Yes	No
fast dye	No	No	Yes	No

As verbs, fast dye is a hyponym of dye; that is, fast dye is a word with a more specific, narrower meaning than dye:

Other hyponyms of dye include bronze, dye, stain, deep-dye, impress, yarn-dye, stain, double dye, hand-dye, piece-dye.

dye (noun)	fast dye (noun)
a usually soluble substance for staining or coloring e.g. fabrics or hair

dye (verb)	fast dye (verb)
color with dye	dye with fast colors
color for microscopic study