unpredictable

Unpredictable means something that's hard to figure out or guess what will happen next. It can also mean someone who acts erratically.

When we use this word in everyday conversations, it usually refers to people or situations that are a bit wild and don't follow a normal pattern. For example, if your friend is unpredictable at parties, you never know what they'll say or do next. They might burst into song one minute and then suddenly get really quiet the next. It's not like them to be so moody, but that's just how they are - unpredictable. Sometimes we use this word to describe things like weather: a storm is unpredictable because it can come out of nowhere and change direction quickly.