Modest order husband put in (6)
I believe the answer is:
chaste
'modest' is the definition.
(I've seen this before)
'order husband put in' is the wordplay.
'order' becomes 'caste' (type of social rank or order).
'husband' becomes 'h' (abbreviation).
'put in' means one lot of letters goes inside another.
'caste' enclosing 'h' is 'CHASTE'.
(Other definitions for chaste that I've seen before include "Modest and decent" , "Restrained, modest" , "Modest and virtuous" , "virgin" , "Refraining from sex" .)