outline vs adumbrate

outline is a noun but adumbrate is not a noun.

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

As verbs, outline and adumbrate are synonyms defined as:

outline and adumbrate: describe roughly or briefly or give the main points or summary of

Other synonyms of outline include sketch.

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

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