Set right about frock (7)
I believe the answer is:
redress
'set right' is the definition.
(I've seen this before)
'about frock' is the wordplay.
'about' becomes 're' (regarding).
'frock' becomes 'dress' ('dress' can be a synonym of 'frock').
're'+'dress'='REDRESS'
(Other definitions for redress that I've seen before include "Make amends for" , "Compensate" , "remedy" , "relief" , "Put right" .)