Reason international leader or subordinate ... (8)
I believe the answer is:
inferior
'subordinate' is the definition.
(synonyms)
'reason international leader or' is the wordplay.
'reason' becomes 'infer' (both can mean to deduce).
'leader' suggests taking the first letters.
The first letter of 'international' is 'i'.
'infer'+'i'+'or'='INFERIOR'
(Other definitions for inferior that I've seen before include "Less important, valuable" , "Subordinate" , "Poorer in quality" , "Of poor quality" , "strictly for the birds" .)