sketch vs chalk out

sketch is a noun but chalk out is not a noun.

Word	Noun	Adjective	Verb	Adverb
sketch	Yes	No	Yes	No
chalk out	No	No	Yes	No

As verbs, sketch and chalk out are synonyms defined as:

sketch (noun)	chalk out (noun)
preliminary drawing for later elaboration
short descriptive summary (of events)
a humorous or satirical drawing published in a newspaper or magazine
a brief literary description

sketch (verb)	chalk out (verb)
describe roughly or briefly or give the main points or summary of	make a sketch of
make a sketch of