suspicious

Suspicious means thinking or feeling that something might not be quite right, like a secret or an unusual behavior.

When people use this word, they usually mean that someone or something has caught their attention because it seems weird or doesn't add up. For example, if you're walking home from work and see someone lurking around your neighborhood at night, you might think they look suspicious. You might not know exactly what's going on, but something about them makes you wonder. The same thing can happen with events – like a fire that happens in an old building or a strange traffic accident. People might say it was suspicious because there are things that don't make sense about it.

In some cases, the word "suspicious" is used to describe someone's behavior, especially if they're trying to hide something. For example, a teacher might think a student looks suspicious when they find out that their math homework has all the answers correct but no signs of effort. This doesn't necessarily mean the student cheated, but it does raise some questions.