1. A tendency to stress the negative or unfavorable or to take the gloomiest possible view: "We have seen too much defeatism, too much pessimism, too much of a negative approach" (Margo Jones).
2. The doctrine or belief that this is the worst of all possible worlds and that all things ultimately tend toward evil.
3. The doctrine or belief that the evil in the world outweighs the good.
[French pessimisme (on the model of optimisme, optimism), from Latin pessimus, worst; see ped- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.