The opposite of noisy is noiseless or quiet. The former is characterized by noise, which means unpleasant, incessant or loud sound. Its antonyms, such as noiseless or quiet, therefore denote the absence of noise.
A sound is considered noisy when it is out of pitch, harmony and control. Example of noisy environments include night clubs, a street with heavy traffic, and barking dogs. Constant exposure to noise may lead to hearing loss and stress. If a sound is pleasing to the ears and creates a desired effect, it then is considered music. However, noise can also be used in creative ways and even has its own music genre, known as noise music.