Mechanic’s unfortunate bad luck (9)
I believe the answer is:
mischance
'bad luck' is the definition.
(mischance is a kind of bad luck)
'mechanic's unfortunate' is the wordplay.
'unfortunate' is an anagram indicator.
'mechanics' is an anagram of 'MISCHANCE'.
(Other definitions for mischance that I've seen before include "Unfortunate business" , "Ill fortune" , "An accident of mechanics" , "Bad luck" , "Unfortunate occurrence" .)