Material:
* Polymer: This is the most scientifically accurate term as plastic is made from polymers.
* Resin: This refers to the raw material used to make plastic.
* Synthetic: This emphasizes that it's man-made.
* Synthetic material: This is a more general term for any man-made material.
* Non-biodegradable: This emphasizes the environmental impact.
Attribute:
* Flexible: If you're talking about the material's flexibility.
* Moldable: If you're talking about its ability to be shaped.
* Artificial: If you want to emphasize its man-made nature.
Figurative meaning:
* Fake: If you're talking about something being artificial or not genuine.
* Superficial: If you're talking about something being shallow or lacking substance.
To give you the best answer, please tell me the context in which you want to use a synonym for "plastic".