fundamentalist vs Protestant

fundamentalist and Protestant both are nouns.

Word	Noun	Adjective	Verb	Adverb
fundamentalist	Yes	Yes	No	No
Protestant	Yes	Yes	No	No

As nouns, Protestant is a hypernym of fundamentalist; that is, Protestant is a word with a broader meaning than fundamentalist:

fundamentalist (noun)	Protestant (noun)
a supporter of fundamentalism	the Protestant churches and denominations collectively
an adherent of fundamentalist principles	an adherent of Protestantism

fundamentalist (adjective)	Protestant (adjective)
of or relating to or characteristic of Protestant fundamentalism or its adherents	of or relating to Protestants or Protestantism
of or relating to or tending toward ideological fundamentalism