menace
Someone or something that causes danger, trouble, or annoyance.
A menace is someone or something that causes trouble, danger, or annoyance to others. When a bully becomes a menace on the playground, they make recess unpleasant or unsafe for other kids. A driver speeding through a neighborhood is a menace to everyone walking or playing nearby.
The word can describe serious threats or lighter troubles. A hurricane approaching the coast is a menace to homes and lives. But your little brother might be called a menace when he keeps interrupting your homework or hiding your things, even though he's not truly dangerous.
You can also use menace as a verb, meaning to threaten or endanger. Storm clouds menace a baseball game. An aggressive dog might menace mail carriers on their route.
The word carries a sense that the danger or trouble is persistent and hard to avoid. A single mistake isn't a menace, but someone who repeatedly causes problems becomes one. When people call something a menace, they're usually suggesting it needs to be stopped or dealt with before it causes more harm.