Girl in mist going over lake (5)
I believe the answer is:
hazel
'girl' is the definition.
'mist going over lake' is the wordplay.
'mist' becomes 'haze' (I've seen this before).
'going over' is a charade indicator (letters next to each other).
'lake' becomes 'l'.
'haze'+'l'='HAZEL'
'in' is the link.
(Other definitions for hazel that I've seen before include "Catkin-bearing tree" , "Type of nut" , "Filbert" , "Tree - greenish-brown" , "Nut-bearing tree" .)