Girl in middle of lake in raincoat (6)
I believe the answer is:
anorak
'raincoat' is the definition.
(I've seen this before)
'girl in middle of lake' is the wordplay.
'girl' becomes 'nora' (**).
'in' is an insertion indicator.
'middle of' means to look at the middle letters.
The central letters of 'lake' are 'ak'.
'nora' placed within 'ak' is 'ANORAK'.
'in' is the link.
(Other definitions for anorak that I've seen before include "Coat - nerd" , "trainspotter" , "Arctic jacket: nerd" , "Casual outerwear" , "Boringly obsessive person" .)