What does hissing mean?

Every cat owner is familiar with the sharp, sibilant sound of hissing— the noise cats make to express fear, aggression, displeasure or uncertainty. Because hissing is your cats way of saying something’s wrong, you should never punish him for the behavior, but rather seek to understand what’s upsetting him.
 
Cats hiss by forcing air out through their arched tongues, creating a burst of wind from their mouths. Other behaviors that accompany hissing include your cat pulling his lips back, flattening his ears to his head and arching his back in a threatening stance. The whole purpose of the disturbing display is to express a warning— that a stranger is too close, that your pet feels threatened or that something is hurting your cat. While he uses hissing to ward off potential opponents and avoid fights, it’s a warning sign that aggression will follow if the perceived threat doesn’t cease and you should take this threat seriously. To avoid being bitten or scratched, you need to understand what is causing Kitty’s conniption fits. Cats hiss due to territorial aggression, for example, especially when a new pet is introduced to the home. Assess any recent changes to you pet’s environment, being sure to introduce newcomers slowly by confining the new pet for the first few days to allow the cats adjust to each other’s scents. If your cat is hissing at human strangers, give guests with advanced warning before they visit and gradually introduce your cat to trusted outsiders so he learns that company isn’t a always a threat. Cats also hiss when they feel scared. If this is the case, take steps to make your pet feel more comfortable in his home: Provide Kitty with plenty of hiding places, perches and other nooks, and consider using Feliway, a mood-enhancing synthetic pheromone that signals feelings of comfort for cats. If your cat is hissing due to aggression, however, the solution may be more play to expel pent-up energy and providing outlets such as scratching posts. Cats also hiss when they’re forced to do something they don’t want to do, such as get in the pet carrier, and the best solution for this type of fit is to remain calm and introduce the undesirable activity slowly so your pet has time to adjust. If all else fails and you must get your cat to do the undesirable, use thick gloves or oven mitts to avoid being scratched.
 
If none of the above sounds like your pet, he may be hissing due to pain, injury or discomfort. Consult your veterinarian to rule out any medical causes if your cat has started hissing or has ramped up the behavior recently and you can’t figure out why. Remember, hissing is a sign that something’s wrong and you should never punish your cat for the behavior. Instead, work to discover the underlying problem and address it so Kitty feels safe and secure in his home.