outline vs synopsis

outline and synopsis both are nouns.

Word	Noun	Adjective	Verb	Adverb
outline	Yes	No	Yes	No
synopsis	Yes	No	No	No

As nouns, outline and synopsis are synonyms defined as:

outline and synopsis: a sketchy summary of the main points of an argument or theory

Other synonyms of outline include abstract, precis.

outline (noun)	synopsis (noun)
a schematic or preliminary plan	a sketchy summary of the main points of an argument or theory
a sketchy summary of the main points of an argument or theory
the line that appears to bound an object

outline (verb)	synopsis (verb)
describe roughly or briefly or give the main points or summary of
trace the shape of
draw up an outline or sketch for something