Hibernian player's backside is pinched by international hard! (5)
I believe the answer is:
irish
'hibernian' is the definition.
(I've seen this before)
'player's backside is pinched by international hard' is the wordplay.
'backside' suggests the final letters (the letter at the back).
'pinched by' is an insertion indicator (inserted letters get pinched or taken).
'international' becomes 'i' (abbreviation eg in IMF).
'hard' becomes 'h' (abbreviation used in pencil classifications).
The final letter of 'player' is 'r'.
'r'+'is'='ris'
'i'+'h'='ih'
'ris' inserted into 'ih' is 'IRISH'.
(Other definitions for irish that I've seen before include "Reddish-brown dog" , "like Wexford" , "Relating to Ireland" , "race" , "of European country" .)