Marriageable bachelor meeting Greek character on French island (6)
I believe the answer is:
nubile
'marriageable' is the definition.
(I know that marriageable can be written as nubile)
'bachelor meeting greek character on french island' is the wordplay.
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'meeting' is a charade indicator (letters next to each other).
'greek character' becomes 'nu' (letter from the Greek alphabet).
'on' is a charade indicator (letters next to each other).
'french island' becomes 'ile' ('island' in French).
'b' after 'nu' is 'nub'.
'nub'+'ile'='NUBILE'
(Other definitions for nubile that I've seen before include "Marriageable, physically attractive" , "Of marriageable age?" , "Sexually attractive" , "fit for match" , "Of girls or women who are eligible to marry" .)