Definition of "unpredictable"

Sharks are not unpredictable; for the most part, they do exactly what an apex predator is expected to do.

1983, Richard Ellis, The Book of Sharks, Knopf, page 146

Other unpredictables, like the recent unexpected blizzards and those of 2 years ago, or a hurricane can cost us many thousands of dollars, and have a severe impact on equipment and facilities.

1960, United States. Congress. Senate. Committee on Interstate and Foreign Commerce. Subcommittee on Surface Transportation, Motor Vehicle Safety: Hearing..., page 12