unpredictable

The word “unpredictable” means impossible to know or foresee in advance. In plain terms, impossible to guess what will happen next.

Here is “unpredictable” used in a sentence: “His moods were unpredictable, swinging from cheerful to furious in minutes.”

“Unpredictable” is an adjective.

“Unpredictable” is an uncommon word in modern English, usually learned at around the B1 level.

Unpredictable means an outcome cannot be foreseen in advance, often because too many variables are involved, while random specifically means outcomes occur without any pattern or cause at all. Weather can be unpredictable due to complex factors, whereas a coin flip is random because each outcome is equally likely with no discernible cause.

Unpredictable can be neutral or even positive depending on context, such as praising an unpredictable plot twist in a film, but it is often used negatively to describe unreliable behavior or unstable situations, such as an unpredictable temper.

Yes, unpredictable is used for people, such as someone with an unpredictable temperament, and for events, such as unpredictable weather or unpredictable markets. In both cases it means the future behavior or outcome cannot be reliably foreseen.