sketch vs sum-up

sketch and sum-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
sketch	Yes	No	Yes	No
sum-up	Yes	No	No	No

As nouns, sum-up is a hypernym of sketch; that is, sum-up is a word with a broader meaning than sketch:

Other hypernyms of sketch include summary.

sketch (noun)	sum-up (noun)
preliminary drawing for later elaboration	a brief statement that presents the main points in a concise form
short descriptive summary (of events)
a humorous or satirical drawing published in a newspaper or magazine
a brief literary description

sketch (verb)	sum-up (verb)
describe roughly or briefly or give the main points or summary of
make a sketch of