University pressure? A stimulant is the answer (5)
I believe the answer is:
upper
'stimulant is the answer' is the definition.
(upper can mean a stimulant drug)
'university pressure? a' is the wordplay.
'university' becomes 'u' (abbreviation for university).
'pressure?' becomes 'p' (abbreviation).
'a' becomes 'per' (eg 'one a day' means 'one per day').
'u'+'p'+'per'='UPPER'
(Other definitions for upper that I've seen before include "Part of shoe above sole" , "person marking swans on Thames?" , "Higher; more northerly" , "Pep pill" , "Top of shoe; stimulant" .)