Murphy, it seems, has nothing to shoot at (6)
I believe the answer is:
potato
'murphy' is the definition.
(synonyms)
'nothing to shoot at' is the wordplay.
'nothing' becomes 'O' (O resembles 0).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'shoot' becomes 'pot' (I've seen this in other clues).
'pot'+'at'='potat'
'o' after 'potat' is 'POTATO'.
'it seems has' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for potato that I've seen before include "Would be difficult to deal with if hot" , "Root vegetable" , "The humble spud" , "Murphy (informal)" , "Common vegetable" .)