Distinguished academic receiving alien back (5)
I believe the answer is:
noted
'distinguished' is the definition.
(I've seen this before)
'academic receiving alien back' is the wordplay.
'academic' becomes 'don' (type of academic - especially at Oxbridge).
'receiving' is an insertion indicator.
'alien' becomes 'et' (extraterrestrial).
'back' is a reversal indicator.
'don' enclosing 'et' is 'deton'.
'deton' written backwards gives 'NOTED'.
(Other definitions for noted that I've seen before include "Made a record - celebrated" , "Celebrated, eminent" , "Indicated" , "Wrote it down" , "Gaiter; oyster spawn" .)