Scholar's beast: Scotsman catching on (7)
I believe the answer is:
oxonian
'scholar's' is the definition.
(I've seen this before)
'beast scotsman catching on' is the wordplay.
'beast' becomes 'ox'.
'scotsman' becomes 'ian' (common Scottish name).
'catching' means one lot of letters goes inside another.
'ox'+'ian'='oxian'
'oxian' enclosing 'on' is 'OXONIAN'.
(Other definitions for oxonian that I've seen before include "up amongst the best?" , "Relating to England's oldest university" , "Resident of the oldest English university city" , "Native of Oxford (University)" , "varsity type" .)