Double-Cross
To break a promise in a way that harms the person with whom the deal was originally struck. To double-cross is to back-stab and to two-time.
Also, double-crossing can be merely 'ratting' someone out.
Also, double-crossing can be merely 'ratting' someone out.
Example:
Vic was double-crossed by his friend Alan, who informed Nelson Fingers of the upcoming deal.
Vic was double-crossed by his friend Alan, who informed Nelson Fingers of the upcoming deal.