
Implacable
Unappeasable Anger
 Used when someone cannot be calmed or pacified, usually due to deep anger or hurt. 
The judge's decision left the victims' families implacable.
 Not For Bargaining
 Indicates that no offering or argument will change a person's negative stance or mood. 
Despite the concessions, the workers remained implacable.
 No Signs of Softening
 Suggests that time or circumstances do not reduce the intensity of someone's resentment. 
Her implacable stance on the issue lasted for years.