Chance I’m terrible engineer (8)
I believe the answer is:
mechanic
'engineer' is the definition.
(thesaurus)
'chance i'm terrible' is the wordplay.
'terrible' is an anagram indicator.
'chance'+'im'='chanceim'
'chanceim' with letters rearranged gives 'MECHANIC'.
(Other definitions for mechanic that I've seen before include "Craftsman skilled in machines" , "Engineer" , "Skilled repairer" , "skilled workman" , "Skilled worker on machines" .)