Thin Market

What Does Thin Market Mean?
A market with a low number of buyers and sellers. Since few transactions take place in a thin market, prices are often more volatile and assets are less liquid. The low number of bids and asks will also typically result in a larger spread between the two quotes.

Also known as a "narrow market".

Investopedia explains Thin Market
A thin market has high price volatility and low liquidity. If supply or demand changes abruptly, resulting in more buyers than sellers or vice versa, there will typically be a material impact on prices. Since few bids and asks are quoted, potential buyers and sellers may find it difficult to transact in a thin market.