desensitized

Desensitized describes a state of reduced sensitivity or responsiveness, whether physical or emotional.

In medical contexts, someone may be desensitized to an allergen through gradual exposure.

More commonly, the word describes emotional numbing—becoming less shocked or disturbed by something through repeated exposure: Years of covering violent crime had desensitized her to gruesome details.

The implication is often negative, suggesting a loss of appropriate feeling or reaction that was once present.