The phrase "most heart-struck" refers to a state of extreme emotion and vulnerability. Its antonyms relate to feelings of detachment and indifference. Words like "unaffected," "unemotional," and "unimpressed" all denote a lack of emotional response. Other antonyms include "callous," "insensitive," and "cold-hearted," all of which suggest a lack of empathy or concern. When someone is not "heart-struck," they may be described as being stoic, aloof, or reserved. In contrast, emotional terms like "passionate," "enthusiastic," and "excited" imply a strong response to a given situation or event.