University philosophy student inclined to be hard going (6)
I believe the answer is:
uphill
'inclined to be hard going' is the definition.
'university philosophy student' is the wordplay.
'university' becomes 'u'.
'philosophy' becomes 'phil'.
'student' becomes 'l'.
'u'+'phil'+'l'='UPHILL'
(Other definitions for uphill that I've seen before include "Difficult situation" , "Epithet for hard struggle" , "Inclined" , "Ascending - arduous" , "Difficult, like steep slope" .)