Youngster parking at university (3)
I believe the answer is:
pup
'youngster' is the definition.
(a pup is a young dog)
'parking at university' is the wordplay.
'parking' becomes 'p' (abbreviation on road signs).
'at university' becomes 'up' ('up' can mean studying at university).
'p'+'up'='PUP'
(Other definitions for pup that I've seen before include "Produce litter" , "Canine young" , "Small palindromic dog" , "Young seal" , "Youngster" .)