pseudoscience vs false belief

pseudoscience and false belief both are nouns.

Word	Noun	Adjective	Verb	Adverb
pseudoscience	Yes	No	No	No
false belief	Yes	No	No	No

As nouns, false belief is a hypernym of pseudoscience; that is, false belief is a word with a broader meaning than pseudoscience:

pseudoscience: an activity resembling science but based on fallacious assumptions
false belief: a misconception resulting from incorrect reasoning

Other hypernyms of pseudoscience include fallacy.

pseudoscience (noun)	false belief (noun)
an activity resembling science but based on fallacious assumptions	a misconception resulting from incorrect reasoning