cornetist vs trumpeter

cornetist and trumpeter both are nouns.

Word	Noun	Adjective	Verb	Adverb
cornetist	Yes	No	No	No
trumpeter	Yes	No	No	No

As nouns, cornetist and trumpeter are synonyms defined as:

cornetist (noun)	trumpeter (noun)
a musician who plays the trumpet or cornet	large gregarious crane-like bird of the forests of South America having glossy black plumage and a loud prolonged cry; easily domesticated
	large pure white wild swan of western North America having a sonorous cry
	a musician who plays the trumpet or cornet
	(formal) a person who announces important news