A University teacher sacking University forecaster (5)
I believe the answer is:
augur
'university forecaster' is the definition.
'augur' can be an answer for 'forecaster' (position in ancient Rome). I am not certain of the 'university' bit.
'a university teacher sacking' is the wordplay.
'university' becomes 'u' (abbreviation for university).
'teacher sacking' becomes 'gur' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a'+'u'+'gur'='AUGUR'
(Other definitions for augur that I've seen before include "Roman diviner" , "Foretell from signs" , "Be an omen (of) - Roman religious official" , "Signal" , "Bode (usu. well or ill)" .)