basic assumption vs assumption

basic assumption and assumption both are nouns.

Word	Noun	Adjective	Verb	Adverb
basic assumption	Yes	No	No	No
assumption	Yes	No	No	No

As nouns, assumption is a hypernym of basic assumption; that is, assumption is a word with a broader meaning than basic assumption:

Other hypernyms of basic assumption include supposal, supposition.

basic assumption (noun)	assumption (noun)
an assumption that is basic to an argument	the act of taking possession of or power over something
	the act of assuming or taking for granted
	audacious (even arrogant) behavior that you have no right to
	a hypothesis that is taken for granted
	a statement that is assumed to be true and from which a conclusion can be drawn