Opposition.
ETYM Greek, to struggle against; anti against + agon contest: cf. French antagonisme. Related to Agony.
1. Being an opposing principle or force or factor.
2. An actively expressed feeling of dislike and hostility.
3. (Biochemistry) Interference in or inhibition of the physiological action of a chemical substance by another having a similar structure.
1. Fight, battle, war
2. Competitive or opposing action of incompatibles; antagonistic state or action (as of divergent ideas, interests, or persons); mental struggle resulting from incompatible or opposing needs, drives, wishes, or external or internal demands
3. The opposition of persons or forces that gives rise to the dramatic action in a drama or fiction