Lacking any guts, endeavour to bung me in lake (4)
I believe the answer is:
mere
'lake' is the definition.
(mere is a kind of lake)
'lacking any guts endeavour to bung me' is the wordplay.
I cannot quite understand how this works, but
'me' is within the answer.
The remaining letters 're' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'in' acts as a link.
Can you help me to learn more?
(Other definitions for mere that I've seen before include "See 13" , "Lake - French mother" , "Pool, small lake" , "Simply, nothing more than" , "Just an English lake" .)