Pessimism; a gloomy or negative outlook—taking a discouraged or despairing view of situations (can be used as a noun or with suru as a verb).
彼はいつも悲観的な意見ばかり言う。
He always says pessimistic things.
悲観する前に、できることを考えよう。
Before being pessimistic, let's think about what we can do.
悲観的な見通しが広がり、市場は下落した。
Pessimistic forecasts spread and the market fell.