* Formal: The two political parties had an antagonistic relationship, rarely cooperating on legislation.
* Informal: My cat and dog have an antagonistic relationship; they hiss and growl at each other constantly.
* Figurative: The artist's bold use of color created an antagonistic effect, clashing with the muted tones of the surrounding paintings.
* Scientific: The study found that the new drug had an antagonistic effect on the existing medication, reducing its effectiveness.
* Literary: The villain's antagonistic actions fueled the hero's determination to save the kingdom.
The word "antagonistic" implies opposition, hostility, or a clashing of interests.