The noun pessimism means a belief that bad things are going to happen.

Synonyms are cynicism, despair, gloom, or melancholy.

The word origins from French (1794) pessimism meaning “worst condition possible”. It also comes from Latin pessimus meaning “worst” perhaps originally “bottom-most”.

Her pessimism made her stop putting more efforts.

I can sense in her tone an underlying pessimism.

A mood of deepening pessimism sweeps over the nation’s economy.