Turning up, upper-class gent is discouraged (3,3)
I believe the answer is:
put off
'is discouraged' is the definition.
(I've seen this before)
'turning up upper-class gent' is the wordplay.
'turning' says the letters should be written in reverse.
'upper-class gent' becomes 'toff' (term for an upper-class person. I am not sure about the 'upper-class' bit.).
'up' reversed gives 'pu'.
'pu'+'toff'='PUT-OFF'
Can you help me to learn more?
(Other definitions for put off that I've seen before include "Defer - deter" , "Deter; delayed" , "Postpone, repel" , "Postpone or dissuade" , "confuse" .)