sketch vs sketchy

sketch is a noun but sketchy is not a noun.

Word	Noun	Adjective	Verb	Adverb
sketch	Yes	No	Yes	No
sketchy	No	Yes	No	No

sketch (noun)	sketchy (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 (adjective)	sketchy (adjective)
	giving only major points; lacking completeness

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