Go to prison? One's a shining light (6)
I believe the answer is:
beacon
'shining light' is the definition.
(a beacon is a bright light)
I cannot understand how the remainder of the clue works.
(Other definitions for beacon that I've seen before include "Prominent light on a hill" , "Navigational guide" , "Fire on a hill, lit as a signal" , "Warning fire or signal" , "A warning light as on headland" .)