Allergy tos refers to the condition of having a hypersensitive reaction to certain substances or allergens, such as pollen, dust, or certain types of food. However, there are various antonyms which can be used to describe the opposite of allergy tos. For instance, tolerance is a term which refers to the ability of the body to withstand or adapt to foreign substances without experiencing an adverse reaction. Similarly, resistance may be used to describe the body's ability to fight off allergens and prevent allergic reactions from occurring. Other potential antonyms for allergy tos may include immunity, acclimation, or adaptation, depending on the specific context and usage.