Ill-treat young lady touring university quarter (6)
I believe the answer is:
misuse
'ill-treat' is the definition.
(I've seen this before)
'young lady touring university quarter' is the wordplay.
'young lady' becomes 'miss' (term of address for a young woman).
'touring' means one lot of letters goes inside another (tour can mean to go around).
'university' becomes 'U' (abbreviation as in UMass).
'quarter' becomes 'e'.
'miss' going around 'u' is 'misus'.
'misus'+'e'='MISUSE'
(Other definitions for misuse that I've seen before include "Ill-treatment" , "Mistreat, misapply" , "Treat the wrong way or for the wrong purpose" , "bad treatment" , "poor employment" .)