Antagonism

Antagonism may refer to:


 * The characteristic of an antagonist
 * Antagonism (chemistry), where the involvement of multiple agents reduces their overall effect
 * Drug antagonism, a drug that stops the action or effect of another substance, preventing a biological response
 * Receptor antagonism or pharmacological antagonism, the action of a drug that inhibits the function of an agonist at the level of a receptor
 * Antagonism (phytopathology), an effect that suppresses the activity of a plant pathogen
 * Reflexive antagonism of muscles
 * Intraspecific antagonism, disharmonious or antagonistic interaction between two individuals of the same species