emphasizing or thinking of the bad part of a situation rather than the good part, or the feeling that bad things are more likely to happen than good things

There is now a mood of deepening pessimism about/over the economy. 目前对经济的悲观情绪越来越浓。

An underlying pessimism infuses all her novels. 她所有的小说中都暗含着一种悲观主义情绪。