Fish around lake for dope? (4)
I believe the answer is:
clod
'dope?' is the definition.
(I've seen this before)
'fish around lake' is the wordplay.
'fish' becomes 'cod' (cod is a kind of fish).
'around' means one lot of letters goes inside another.
'lake' becomes 'l'.
'cod' placed around 'l' is 'CLOD'.
'for' acts as a link.
(Other definitions for clod that I've seen before include "Lump of earth - nitwit" , "Stupid person - compact lump" , "Block" , "dope?" , "Fool - lump of earth" .)