Greek character meeting thin South American (7)
I believe the answer is:
chilean
'south american' is the definition.
(Chilean is an example)
'greek character meeting thin' is the wordplay.
'greek character' becomes 'chi' (letter from the Greek alphabet).
'meeting' says to put letters next to each other.
'thin' becomes 'lean' ('lean' is associated in meaning with 'thin').
'chi'+'lean'='CHILEAN'
(Other definitions for chilean that I've seen before include "Spanish speaker" , "Native of, eg, Santiago" , "Nationality of citizen of Santiago" , "from South American country" , "Santiago-born" .)