Boris saving skin? He finally left Oxford college (5)
I believe the answer is:
oriel
'oxford college' is the definition.
(Oriel College, Oxford)
'boris saving skin? he finally left' is the wordplay.
'saving skin?' indicates the central letters (the 'skin' of the word is left out or 'saved').
'finally' suggests the final letters.
'left' becomes 'l' (common abbreviation).
The middle letters of 'boris' are 'ori'.
The last letter of 'he' is 'e'.
'ori'+'e'+'l'='ORIEL'
(Other definitions for oriel that I've seen before include "Overhanging recess (window)" , "place to study at Oxford" , "Style of window" , "polygonal recess" , "One could look through this" .)