Repairman to strike during disastrous fire (5)
I believe the answer is:
fixer
'repairman' is the definition.
(I've seen this in another clue)
'strike during disastrous fire' is the wordplay.
'strike' becomes 'x' (I can't explain this - if you can you should give a lot more credence to this answer).
'during' is an insertion indicator.
'disastrous' indicates anagramming the letters.
'fire' anagrammed gives 'fier'.
'x' inserted within 'fier' is 'FIXER'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for fixer that I've seen before include "Chemical in photography" , "Agent" , "One who makes arrangements" .)