Foretell crazy operating cost (13)
I believe the answer is:
prognosticate
'foretell' is the definition.
(synonyms)
'crazy operating cost' is the wordplay.
'crazy' is an anagram indicator.
'operating'+'cost'='operatingcost'
'operatingcost' is an anagram of 'PROGNOSTICATE'.
(Other definitions for prognosticate that I've seen before include "divine" , "Arbitrary" , "Foretell" , "Augur" , "Predict" .)