Some quiet husband is so (4)
I believe the answer is:
thus
'so' is the definition.
(I know that so can be written as thus)
'some quiet husband is' is the wordplay.
'some' indicates the answer is hidden within the clue (some parts of the word are used).
'THUS' is hidden within 'quiet husband is'.
(Other definitions for thus that I've seen before include "Consequently" , "as indicated" , "As a result" , "In this manner" , "It follows" .)