Primary scholar, one in South Carolina (5)
I believe the answer is:
basic
'primary' is the definition.
(thesaurus)
'scholar one in south carolina' is the wordplay.
'scholar' becomes 'ba'.
'one' becomes 'i' (Roman numeral).
'in' means one lot of letters goes inside another.
'south carolina' becomes 'sc'.
'i' going into 'sc' is 'sic'.
'ba'+'sic'='BASIC'
(Other definitions for basic that I've seen before include "Spartan" , "Elementary - without extras" , "Fundamental instruction's" , "Forming a foundation" , "Straightforward" .)