mercer vs trader

mercer and trader both are nouns.

Word	Noun	Adjective	Verb	Adverb
mercer	Yes	No	No	No
trader	Yes	No	No	No

As nouns, trader is a hypernym of mercer; that is, trader is a word with a broader meaning than mercer:

mercer: a dealer in textiles (especially silks)
trader: someone who purchases and maintains an inventory of goods to be sold

Other hypernyms of mercer include bargainer, dealer, monger.

mercer (noun)	trader (noun)
a dealer in textiles (especially silks)	someone who purchases and maintains an inventory of goods to be sold