direct dye vs dyestuff

direct dye and dyestuff both are nouns.

Word	Noun	Adjective	Verb	Adverb
direct dye	Yes	No	No	No
dyestuff	Yes	No	No	No

As nouns, dyestuff is a hypernym of direct dye; that is, dyestuff is a word with a broader meaning than direct dye:

direct dye: dye with a high affinity for cellulose fibers (cotton or rayon etc.)
dyestuff: a usually soluble substance for staining or coloring e.g. fabrics or hair

Other hypernyms of direct dye include dye.

direct dye (noun)	dyestuff (noun)
dye with a high affinity for cellulose fibers (cotton or rayon etc.)	a usually soluble substance for staining or coloring e.g. fabrics or hair