General synonyms:
* Bifurcation: This emphasizes the division into two distinct parts.
* Dualism: This highlights the opposing nature of the two parts.
* Polarity: This emphasizes the extreme opposition of the two parts.
* Split: This is a more informal word that emphasizes the separation of the two parts.
* Contradiction: This emphasizes the inherent conflict between the two parts.
* Divergence: This emphasizes the moving apart of the two parts.
* Disparity: This emphasizes the inequality or difference between the two parts.
More specific synonyms:
* Black and white: This refers to a simplistic view of the world with only two options.
* Either/or: This emphasizes the exclusive nature of the two choices.
* Yin and yang: This refers to a balanced opposition of two complementary forces.
* Good vs. evil: This refers to a classic moral dichotomy.
* Left vs. right: This refers to a political dichotomy.
The best synonym for "dichotomy" will depend on the specific context of your writing. Consider what aspect of the concept you want to emphasize and choose the word that best reflects that nuance.