Bright store window light (4)
I believe the answer is:
neon
(Other definitions for neon that I've seen before include "One of the six inert gasses" , "Inert gas, symbol Ne" , "Sign gas" , "Could it brighten proceedings" , "It may illuminate" .)
I believe the answer is:
neon
(Other definitions for neon that I've seen before include "One of the six inert gasses" , "Inert gas, symbol Ne" , "Sign gas" , "Could it brighten proceedings" , "It may illuminate" .)