The phrase "heart struck" typically describes a feeling of emotional overwhelm and intense affection or fascination for someone or something. Antonyms for "heart struck" may include emotionally indifferent, emotionally unaffected, emotionally cold, emotionally distant, emotionally disengaged, emotionally detached, emotionally uninvolved, emotionally unfeeling, emotionally unresponsive, or emotionally numb. These words suggest a lack of emotion, interest, or feeling, rather than the strong emotional reaction implied by "heart struck." So, if someone is not "heart struck," they are most likely disconnected and dispassionate about the subject or the person.