Bomb may not be if it has this (2,3)
I believe the answer is:
of use
'if it has this' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'bomb may not' is the wordplay.
I cannot quite understand how this works, but
'not' could be 'o' (I've seen this in other clues) and 'o' is located in the answer.
The remaining letters 'fuse' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'be' acts as a link.
Can you help me to learn more?
(Other definitions for of use that I've seen before include "practical" , "Employable" , "Serviceable" , "Having a function" , "Helpful" .)