For "essence" meaning the most important part or characteristic:
* Superficiality: focusing on the surface level rather than the core.
* Insignificance: lacking importance or meaning.
* Triviality: something of little value or importance.
* Extraneous: not essential or relevant.
For "essence" meaning the true nature of something:
* Illusion: a false or misleading perception.
* Facade: a superficial appearance that hides the true nature.
* Sham: something that is not genuine or real.
* Appearance: the way something looks, rather than what it is.
For "essence" meaning a concentrated extract:
* Dilution: making something less concentrated.
* Impurity: something that is not pure or unmixed.
* Refinement: removing impurities or undesirable elements.
For "essence" meaning a spiritual or philosophical concept:
* Materialism: focusing on the physical world rather than spiritual or abstract concepts.
* Pragmatism: focusing on practical concerns rather than theoretical or philosophical ideas.
* Nihilism: the belief that life is meaningless and without purpose.
The best antonym will depend on the specific context in which you're using the word "essence."