Some gas to release around outlet (9)
I believe the answer is:
megastore
'outlet' is the definition.
(I have seen 'large outlet' mean 'megastore' so perhaps 'outlet' could also mean 'megastore')
'some gas to release around' is the wordplay.
'around' indicates the answer is hidden within the clue.
'MEGASTORE' can be found hidden inside 'some gas to release'.
(Other definitions for megastore that I've seen before include "giant in business" , "Very large shop" , "Massive outlet" , "large outlet" .)