summary vs compendious

summary is a noun but compendious is not a noun.

Word	Noun	Adjective	Verb	Adverb
summary	Yes	Yes	No	No
compendious	No	Yes	No	No

As adjectives, summary and compendious are synonyms defined as:

Other synonyms of summary include compact, succinct.

summary (noun)	compendious (noun)
a brief statement that presents the main points in a concise form

summary (adjective)	compendious (adjective)
briefly giving the gist of something	briefly giving the gist of something
performed speedily and without formality