Capital husband invested in food retail outlet (5)
I believe the answer is:
delhi
'capital' is the definition.
(New Delhi is the capital of India)
'husband invested in food retail outlet' is the wordplay.
'husband' becomes 'h' (abbreviation).
'invested in' indicates putting letters inside.
'food retail outlet' becomes 'deli' (short for delicatessen).
'h' going into 'deli' is 'DELHI'.
(Other definitions for delhi that I've seen before include "Indian state" , "Capital at one time" , "It's also new in India" , "Plumbing ring" , "Capital on the river Jumna" .)