n.
- a person who actively opposes or is hostile towards someone or something.
- Biochemistry a substance which interferes with the physiological action of another.
- Anatomy a muscle whose action counteracts that of another muscle.
Derivative
- antagonistic adj.
- antagonistically adv.
Etymology
C16: from Fr. antagoniste or late L. antagonista, from Gk antagōnistēs, from antagōnizesthai (see antagonize); cf. agonist.