The antonyms for the word over-sensitive are unfeeling, thick-skinned, and insensitive. Unfeeling refers to a person who is indifferent or apathetic to emotional stimuli, while thick-skinned implies that a person is highly resilient to criticism or discomfort. Insensitive refers to a lack of awareness, empathy, or concern for others. These antonyms oppose the idea of a person who is highly responsive to emotional stimuli, easily offended, or prone to overreact. Someone who is unfeeling, thick-skinned, or insensitive might be perceived as callous, impervious, or lacking in emotional depth.