scholar vs quick study

scholar and quick study both are nouns.

Word	Noun	Adjective	Verb	Adverb
scholar	Yes	No	No	No
quick study	Yes	No	No	No

As nouns, quick study is a hyponym of scholar; that is, quick study is a word with a more specific, narrower meaning than scholar:

scholar: someone (especially a child) who learns (as from a teacher) or takes up knowledge or beliefs
quick study: someone able to acquire new knowledge and skills rapidly and easily

Other hyponyms of scholar include memoriser, memorizer, sponge, dweeb, grind, nerd, swot, wonk, tutee.

scholar (noun)	quick study (noun)
a learned person; someone who by long study has gained mastery in one or more disciplines	someone able to acquire new knowledge and skills rapidly and easily
someone (especially a child) who learns (as from a teacher) or takes up knowledge or beliefs
a student who holds a scholarship