poet vs sonneteer

poet and sonneteer both are nouns.

Word	Noun	Adjective	Verb	Adverb
poet	Yes	No	No	No
sonneteer	Yes	No	No	No

As nouns, sonneteer is a hyponym of poet; that is, sonneteer is a word with a more specific, narrower meaning than poet:

poet: a writer of poems (the term is usually reserved for writers of good poetry)
sonneteer: a poet who writes sonnets

Other hyponyms of poet include bard, elegist, odist, poetess, poet laureate, poet laureate.

poet (noun)	sonneteer (noun)
a writer of poems (the term is usually reserved for writers of good poetry)	a poet who writes sonnets