1. A state of reduced or absent immune response to a specific antigen, despite the presence of that antigen in the body.
Usage: medical/immunology term; often used in clinical and research contexts
2. Lack of energy or motivation; lethargy or apathy.
Usage: rare; archaic or literary usage

Examples

• The patient developed anergy to the tuberculin skin test after prolonged immunosuppression.
• Anergy can occur in advanced HIV infection, making standard immune tests unreliable.
• Researchers are studying how to reverse anergy in cancer patients to improve immunotherapy outcomes.
• The drug-induced anergy prevented the body from mounting an effective response to the vaccine.
• Anergy to common antigens is a hallmark of severe immunodeficiency.