Confirmed international tariff will include new event (10)
I believe the answer is:
inveterate
'confirmed' is the definition.
(thesaurus)
'international tariff will include new event' is the wordplay.
'international' becomes 'i' (abbreviation eg in IMF).
'tariff' becomes 'rate' (I've seen this before**).
'will include' indicates putting letters inside.
'new' indicates anagramming the letters.
'i'+'rate'='irate'
'event' with letters rearranged gives 'nvete'.
'irate' placed around 'nvete' is 'INVETERATE'.
(Other definitions for inveterate that I've seen before include "Firmly established by usage or custom" , "Long-formed (bad habit)" , "Habitual" , "Long-established" , "Hardened" .)