Fish without batter? Sense it’s fishy (5,1,3)
I believe the answer is:
smell a rat
'fish without batter?' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'sense it's fishy' is the wordplay.
I cannot quite understand how this works, but
'sense' could be 'smell' (smelling is a kind of sensing) and 'smell' is present in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found in the answer.
The remaining letters 'ara' 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).
Can you help me to learn more?
(Other definitions for smell a rat that I've seen before include "Sense something suspicious" , "Suspect deception" , "Sense something is amiss" , "Detect something suspicious" , "Suspect something wrong" .)