In the context of the cryptocurrency industry, being bearish is being confident that a particular blockchain platform or cryptocurrency is going to sharply decrease in value
Bearish is the opposite to Bullish.
If an investor is feeling bearish about a particular cryptocurrency, they will sell their stock of cryptocurrency at the earliest opportunity. This is because if the value decreases as they expect, then the earlier they sell, the more of a return they will make, rather than losing money as the value decreases.
The reasons for an investor being bearish in the cryptocurrency industry would be almost exactly the same as they would for an individual investing in a company on the stock market. The news cycle is a key indicator, along with the regulatory situations in different countries. For example, prices tend to decrease, when countries openly criticize and regulate cryptocurrencies.