pessimistic

Marked by pessimism and little hopefulness; expecting the worst.

a pessimistic view of the future

Pertaining to the worst-case scenario.

a pessimistic estimate

However pessimistic their predictions, most scientists and scholars who warn of impending disaster are really acting from antidystopian motives.

Taking out exclusive locks on data to prevent conflicts with other processes that might modify it.

pessimistic concurrency; pessimistic locking