Plies drunk working for Greek character (7)
I believe the answer is:
epsilon
'greek character' is the definition.
(letter from the Greek alphabet)
'plies drunk working' is the wordplay.
'drunk' indicates anagramming the letters.
'working' becomes 'on'.
'plies' is an anagram of 'epsil'.
'epsil'+'on'='EPSILON'
'for' is the link.
(Other definitions for epsilon that I've seen before include "5th letter of the Greek alphabet" , "Greek letter - pinoles (anag)" , "foreign letter" , "character in Greece" , "Fifth letter of the Greek alphabet" .)