comprehensive. adj. 1. of broad scope or content; including all or much. 2. (Insurance) (of a car insurance policy) providing protection against most risks, including third-party liability, fire, theft, and damage.3. having the ability to understand.4. (Education) of, relating to, or being a comprehensive school. n.. of broad scope or content; including all or much. 2. (Insurance) (of a car insurance policy) providing protection against most risks, including third-party liability, fire, theft, and damage. 3. having the ability to understand. 4. (Education) of, relating to, or being a comprehensive school.