The phrase "dead to human feeling" is often used to describe a person who lacks empathy or compassion. There are several synonyms that can be used to convey the same meaning, including heartless, cold-blooded, unfeeling, numb, indifferent, and callous. These words all imply a lack of emotional connection to others, whether it is due to a personality disorder or a conscious choice. While these traits may seem desirable in certain professions, they can also be detrimental to personal relationships and social interactions. It is important to recognize the impact that these characteristics have on ourselves and those around us, and strive to cultivate empathy and kindness.