sketch vs rough drawing

sketch and rough drawing both are nouns.

Word	Noun	Adjective	Verb	Adverb
sketch	Yes	No	Yes	No
rough drawing	Yes	No	No	No

As nouns, rough drawing is a hyponym of sketch; that is, rough drawing is a word with a more specific, narrower meaning than sketch:

Other hyponyms of sketch include design, draft, vignette.

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

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