His age is dodgy for entertaining girl (6)
I believe the answer is:
geisha
'entertaining girl' is the definition.
(I've seen this before)
'his age is dodgy' is the wordplay.
'is dodgy' is an anagram indicator (a dodgy or wrong order of the letters).
'his'+'age'='hisage'
'hisage' is an anagram of 'GEISHA'.
'for' is the link.
(Other definitions for geisha that I've seen before include "Trained Japanese hostess - his age (anag)" , "He's a GI (anag.)" , "Jap. entertainer" , "Japanese hostess who entertains men" , "Jap. hostess" .)