It’s slipshod and over-sentimental (6)
I believe the answer is:
sloppy
This clue could be a double definition.
'it's slipshod' is the first definition.
('sloppy' can be a synonym of 'slipshod')
'sentimental' is the second definition.
(thesaurus)
'and over' is the link.
This may not be correct. Some or all of it may belong to one of the definitions.
Can you help me to learn more?
(Other definitions for sloppy that I've seen before include "Mawkish" , "'Careless, shoddy (6)'" , "Casual; sentimental" , "Slipshod" , "Excessively casual" .)