Retired academics returning — it has to anger me (7)
I believe the answer is:
emeriti
'retired academics' is the definition.
(I've seen this in another clue)
'returning it has to anger me' is the wordplay.
'returning' shows that the letters should be reversed in order.
'has' means one lot of letters go next to another.
'to anger' becomes 'ire' (ire is intense rage).
'it'+'ire'+'me'='itireme'
'itireme' back-to-front is 'EMERITI'.
(Other definitions for emeriti that I've seen before include "Retired title-holders" , "(Of, say, professors) retired, but retaining title" , "Such as retired professors who retain title" , "Eg, retired professors" , "Esteemed quondam staff" .)