pes ‧ si ‧ mi ‧ sm /ˈpesəmɪz ə m, ˈpesɪmɪz ə m/ BrE AmE noun [uncountable]
[ Date: 1700-1800 ; Language: French ; Origin: pessimisme , from Latin pessimus 'worst' ]
a tendency to believe that bad things will happen OPP optimism
pessimism about/over
There is deep pessimism about the future.