Vaginitis: Inflammation of the vagina. The vagina is the muscular canal extending from the cervix to the outside of the body. Vaginitis is often caused by a fungus. A woman with this condition may have itching or burning and may notice a discharge. Vaginitis is a common condition. There are factors that predispose a woman to develop vaginitis. For example, women who have diabetes have vaginitis more often than women who do not.