Open in case of pecuniary hardship (7)
I believe the answer is:
poverty
'hardship' is the definition.
(thesaurus)
'open in case of pecuniary' is the wordplay.
'open' becomes 'overt' ('overt' is associated in meaning with 'open'**).
'in' means one lot of letters goes inside another.
'case of' suggests removing the centre (outsides of).
'pecuniary' with its middle taken out is 'py'.
'overt' placed into 'py' is 'POVERTY'.
(Other definitions for poverty that I've seen before include "Poor state" , "Penury" , "'When ....... comes in at the door, love flies out of the window'" , "Need" , "Indigence" .)