What is Excessive Force?

Legal Definition
Excessive force refers to force in excess of what a police officer reasonably believes is necessary. A police officer may be held liable for using excessive force in an arrest, an investigatory stop, or other seizures. A police officer may also be liable for not preventing another police officer from using excessive force.

Whether the police officer has used force in excess of what he reasonably believed necessary at the time of action is a factual issue to be determined by the jury.
Legal Definition
In a given situation, the use of aggressive capability above expectation. The capability use is deemed unreasonable or unwarranted.
Legal Definition
Force beyond that reasonably necessary to defense of person or property.
-- Ballentine's Law Dictionary