Here's why:
* Sublimation: The process where a solid directly changes into a gas, skipping the liquid phase.
* Deposition: The process where a gas directly changes into a solid, skipping the liquid phase.
It's like the opposite of sublimation.
However, in a psychological context, sublimation is the process of channeling unacceptable impulses into socially acceptable behavior. The antonym in this context would be regression, where someone retreats to an earlier stage of development or behavior.
So, the best antonym for sublimation depends on the context.