a : a dangerous or possibly harmful person or thing — usually singular
Those dogs are a menace.
— often + to
Those dogs are a menace to the neighborhood.
a criminal who is a menace to society
b : someone who causes trouble or annoyance — usually singular
That kid is a menace.
2 [noncount] : a dangerous or threatening quality
There was an atmosphere of menace in the city.
She could hear the menace in his voice.