seamster vs adult male

seamster and adult male both are nouns.

Word	Noun	Adjective	Verb	Adverb
seamster	Yes	No	No	No
adult male	Yes	No	No	No

As nouns, adult male is a hypernym of seamster; that is, adult male is a word with a broader meaning than seamster:

Other hypernyms of seamster include dressmaker, garment-worker, garment worker, garmentmaker, man.

seamster (noun)	adult male (noun)
a person whose occupation is making and altering garments	an adult person who is male (as opposed to a woman)