What parts of speech are the underlined words?
The poor will always be exploited by the rich.
Dean MacIver was a poor player.
Noun, Adjective
The poor will always be exploited by the rich. (Noun, because ‘poor’ is accompanied by the article ‘the’ and it names a class of people.)
Dean MacIver was a poor player. (Adjective, because it describes the noun ‘player’.)