Gamble taken by Raymond and Edward, double-crossed (8)
I believe the answer is:
betrayed
'double-crossed' is the definition.
(I've seen this in another clue)
'gamble taken by raymond and edward' is the wordplay.
'gamble' becomes 'bet' (bet is a kind of gamble).
'taken by' is a charade indicator (letters next to each other).
'raymond' becomes 'ray' (Ray is short for Raymond).
'and' is a charade indicator (letters next to each other).
'edward' becomes 'Ed' (short for Edward).
'bet'+'ray'+'ed'='BETRAYED'
(Other definitions for betrayed that I've seen before include "Unintentionally showed" , "Broke one's promise" , "Double-crossed, abandoned" , "Delivered to an enemy by treachery" , "given away" .)