The word misophonia literally translates to "hatred of sound". Hatred of sound is in fact an understand for those who suffer from this disorder. Misophonia sufferers are extremely sensitive to sound, so much so that they have sometimes violent reactions to a certain set of sounds that they call "triggers".
Much like individuals who suffer from PTSD, those who suffer from misophonia have a set of triggers. In the case of those with a sensitivity to sound, these triggers can be things like; people eating food, the crunching of ice or chips in someones mouth, the sound of a certain persons voice, heavy breathing etc.
Misophonia is not be confused with hyperacusis (a disorder that makes people sensitive to all sounds). Misophonia is purely a sensitivity to a set of "trigger" sounds. It may be very possible for a person suffering from this disorder to have extreme difficult speaking with a certain person simply because of the sound of their voice while still being able to converse with others.
Misophonia is very rarely given as a diagnoses and is currently considered a sensory processing disorder much like PTSD. As a matter of fact, misophonia and PTSD are very closely aligned both in symptoms and diagnoses.