composer vs songster

composer and songster both are nouns.

Word	Noun	Adjective	Verb	Adverb
composer	Yes	No	No	No
songster	Yes	No	No	No

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

Other hyponyms of composer include contrapuntist, psalmist, ballad maker, songwriter, symphonist.

composer (noun)	songster (noun)
someone who composes music, usually as a profession	any bird having a musical call
	a person who sings with skill
	a composer of words or music for popular songs