Bladder infection: Infection of the urinary bladder. Some people are at more risk for bladder and other urinary tract infections (UTIs) than others. Women are at greater risk than men. One woman in five develops a UTI during her lifetime. Not everyone with a UTI has symptoms. Common symptoms include a frequent urge to urinate and a painful, burning when urinating. Underlying conditions that impair the normal urinary flow can lead to more complicated UTIs.