Irish spirit has been modified (7)
I believe the answer is:
banshee
'irish spirit' is the definition.
(I've seen this in another clue)
'has been modified' is the wordplay.
'modified' indicates an anagram.
'has'+'been'='hasbeen'
'hasbeen' anagrammed gives 'BANSHEE'.
(Other definitions for banshee that I've seen before include "She predicts death in Ireland" , "no one wishes to hear" , "'Wailing woman, warns of impending death (7)'" , "Wailing spirit that foretells death" , "Wailing woman warning of a death" .)