Copper right — not many for stay-at-home order (6)
I believe the answer is:
curfew
'stay-at-home order' is the definition.
(a curfew is an order to remain indoors)
'copper right not many' is the wordplay.
'copper' becomes 'Cu' (Cu is the chemical symbol for copper).
'right' becomes 'r' (common abbreviation).
'not many' becomes 'few' ('few' is the opposite to 'many').
'cu'+'r'+'few'='CURFEW'
'for' acts as a link.
(Other definitions for curfew that I've seen before include "Regulation requiring people to be indoors during certain hours" , "Regulation restricting movement at night" , "Early bedtime imposed by military" , "Order to be off the streets by a certain hour" , "Prohibition order" .)