Hawk comes from lake shrouded in mist (4)
I believe the answer is:
flog
'hawk' is the definition.
(both can mean to sell)
'lake shrouded in mist' is the wordplay.
'lake' becomes 'l'.
'shrouded in' indicates putting letters inside.
'mist' becomes 'fog' (synonyms).
'l' going into 'fog' is 'FLOG'.
'comes from' acts as a link.
(Other definitions for flog that I've seen before include "Keep hitting" , "Scourge, whip" , "Beat with a whip or rod" , "- - a dead horse" , "Exchange for money" .)