Ever so proper (4)
I believe the answer is:
prim
'ever so proper' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for prim that I've seen before include "Demure" , "Formally prudish" , "Schoolmarmish" , "Strait-laced - prudish" , "Proper (type of rose?)" .)