Misophonia is sound triggering emotion with unusual force: particular everyday sounds, frequently mouth and breathing noises, produce instant anger or disgust rather than mild annoyance. The reaction is fast, specific to trigger sounds, and hard to override.
It is not synesthesia, but it lives on the same street: a specific auditory trigger reliably producing an involuntary response in another system, in this case emotion. Imaging work has found atypical connectivity between auditory and emotional regions in people with strong misophonia.
The term dates to 2001, the experience is clearly older, and the field around it is young enough that definitions are still settling.