One sorry about daughter becoming less civil (5)
I believe the answer is:
ruder
'less civil' is the definition.
('rude' can be the opposite of 'civil' so perhaps 'ruder' is reasonable for 'less civil')
'one sorry about daughter' is the wordplay.
'one sorry' becomes 'ruer' (a person who rues).
'about' indicates putting letters inside.
'daughter' becomes 'd'.
'ruer' enclosing 'd' is 'RUDER'.
'becoming' acts as a link.
(Other definitions for ruder that I've seen before include "More impudent" , "Less polite" , "less pleasant in manner" , "Coarser" , "comparatively unsophisticated" .)