Reckless drive around Oxford University (9)
I believe the answer is:
impetuous
'reckless' is the definition.
(I've seen this in another clue)
'drive around oxford university' is the wordplay.
'drive' becomes 'impetus' (impetus is a drive to do something).
'around' means one lot of letters goes inside another.
'oxford university' becomes 'OU'.
'impetus' going around 'ou' is 'IMPETUOUS'.
(Other definitions for impetuous that I've seen before include "Acting rashly" , "Rash" , "Impulsive, hasty" , "Hot-headed" .)