pessimistic

adjective3

1. •
   Marked by pessimism and little hopefulness; expecting the worst.

   • Some, noting the obvious analogies between Soviet Communism and Nazism, had pessimistic forebodings as to the inevitability of totalitarian systems throughout the world. — 1978
2. •
   Pertaining to the worst-case scenario.

   • However pessimistic their predictions, most scientists and scholars who warn of impending disaster are really acting from antidystopian motives. — 1996
3. •
   Taking out exclusive locks on data to prevent conflicts with other processes that might modify it.