Celebrate youngster embracing university (4)
I believe the answer is:
laud
'celebrate' is the definition.
(I've seen this in another clue)
'youngster embracing university' is the wordplay.
'youngster' becomes 'lad' (a young boy).
'embracing' means one lot of letters goes inside another.
'university' becomes 'U' (abbreviation as in UMass).
'lad' going around 'u' is 'LAUD'.
(Other definitions for laud that I've seen before include "Give praise to" , "'Praise, glorify (4)'" , "Praise highly" , "Name of archbishop; praise" , "Praise acclaim" .)