basis vs groundwork

basis and groundwork both are nouns.

Word	Noun	Adjective	Verb	Adverb
basis	Yes	No	No	No
groundwork	Yes	No	No	No

As nouns, basis and groundwork are synonyms defined as:

basis and groundwork: the fundamental assumptions from which something is begun or developed or calculated or explained

Other synonyms of basis include base, cornerstone, foundation, fundament.

basis (noun)	groundwork (noun)
the fundamental assumptions from which something is begun or developed or calculated or explained	preliminary preparation as a basis or foundation
a relation that provides the foundation for something	lowest support of a structure
the most important or necessary part of something	the fundamental assumptions from which something is begun or developed or calculated or explained