Short acknowledgement outside university for scoundrel (5)
I believe the answer is:
rogue
'for scoundrel' is the definition.
(rogue is a kind of scoundrel)
'short acknowledgement outside university' is the wordplay.
'short acknowledgement' becomes 'roge' (I can't explain this - if you can you should believe this answer much more).
'outside' indicates putting letters inside (some letters go outside others).
'university' becomes 'U' (abbreviation for university).
'roge' placed around 'u' is 'ROGUE'.
(Other definitions for rogue that I've seen before include "Impish, likeable person" , "Scoundrel, knave" , "Profligate" , "One dishonest" , "Stray" .)