Greek character thus produced pleasing sounds (5)
I believe the answer is:
music
'pleasing sounds' is the definition.
(I've seen this before)
'greek character thus' is the wordplay.
'greek character' becomes 'mu' (letter from the Greek alphabet).
'thus' becomes 'sic' ('sic' can be a synonym of 'thus').
'mu'+'sic'='MUSIC'
'produced' acts as a link.
(Other definitions for music that I've seen before include "melodies" , "Composed sound" , "(Pleasant) sequence of sounds" , "Aural entertainment" , "Art (of noise)" .)