What is "pessimize"

Pessimize \Pes"si*mize\, v. i. To hold or advocate the doctrine of pessimism.
--London Sat. Rev.

vb. 1 To think like a pessimist; to believe the worst. 2 (context transitive English) To make (something) pessimal. 3 (context transitive English) To make (something) less efficient, such as a computer program. 4 (context intransitive English) To become pessimal.