Hiss/hɪs/ Definition 1 of 5Pro Tip 1/2Imitative Sound Use 'hiss' to imitate the actual sound made by animals or objects for vivid description. The radiator hissed as the hot water flowed through it. Pro Tip 2/2Negative Atmosphere 'Hiss' often suggests annoyance or something unwelcome, like danger or discomfort. I could hear the hiss of the snake hidden in the grass.