allergy

noun3

1. •
   A disorder of the immune system causing adverse reactions to substances (allergens) not harmful to most and marked by the body's production of histamines and associated with atopy, anaphylaxis, and asthma; any condition of hypersensitivity to a substance.

   • My dad can't live with pets because of an allergy.
2. •
   Specifically, hypersensitivity of class I in the modern classification thereof: the immunoglobulin E–mediated type.
3. •
   (informal, figurative) An antipathy, as toward a person or activity.

   • He has an allergy to reality TV.