Neoprene is a synthetic polymer. It is produced through the polymerization of chloroprene (2-chloro-1,3-butadiene), a process that is entirely human-made in a laboratory or industrial setting. This distinguishes it from natural polymers, which are derived from nature (like cellulose), and semi-synthetic polymers, which are chemically modified natural polymers (like rayon).

Its chemical structure is based on the repeating unit: $(-{\mathrm{CH}}_2-C=CH-{\mathrm{CH}}_2-)$ with a chlorine atom attached.

Final Answer: synthetic polymer