* Natural: This is the most common opposite, referring to something occurring in nature without human intervention.
* Organic: This implies something derived from living organisms or their processes.
* Real: This emphasizes authenticity and genuineness over artificiality.
* Authentic: Similar to "real," this implies something genuine and not fabricated.
* Naturalistic: This refers to something that resembles or mimics natural processes or forms.
Examples:
* Synthetic fabric vs. Natural fabric (cotton, wool)
* Synthetic sweetener vs. Organic sweetener (honey)
* Synthetic diamond vs. Real diamond
* Synthetic perfume vs. Authentic perfume (made with natural essential oils)
The best opposite for "synthetic" will depend on the specific situation you're discussing.