quick study vs scholar

quick study and scholar both are nouns.

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

As nouns, scholar is a hypernym of quick study; that is, scholar is a word with a broader meaning than quick study:

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

Other hypernyms of quick study include assimilator, learner, student.

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