capricious

Definitions

Given to sudden and unaccountable changes of mood or behavior.

Fickle, unpredictable, or subject to whim.

Examples

The weather in the mountains is notoriously capricious, shifting from bright sunshine to a heavy thunderstorm in a matter of minutes.

Because of his capricious nature, his employees never knew what kind of mood he would be in when he walked through the door.

Synonyms

fickle whimsical mercurial erratic unpredictable volatile impulsive

Antonyms

constant stable consistent predictable steadfast reliable dependable