stockist vs supplier

stockist and supplier both are nouns.

Word	Noun	Adjective	Verb	Adverb
stockist	Yes	No	No	No
supplier	Yes	No	No	No

As nouns, supplier is a hypernym of stockist; that is, supplier is a word with a broader meaning than stockist:

stockist: one (as a retailer or distributor) that stocks goods
supplier: someone whose business is to supply a particular service or commodity

Other hypernyms of stockist include provider.

stockist (noun)	supplier (noun)
one (as a retailer or distributor) that stocks goods	someone whose business is to supply a particular service or commodity