Good-looking girl, timid (5)
I believe the answer is:
dishy
'good-looking' is the definition.
(I've seen this before)
'girl timid' is the wordplay.
'girl' becomes 'di' (**).
'timid' becomes 'shy' ('shy' can be similar in meaning to 'timid').
'di'+'shy'='DISHY'
(Other definitions for dishy that I've seen before include "Good-looking (colloq.)" , "Attractive" , "Gorgeous" , "Handsome" , "Fair" .)