At law, an accomplice is a person who actively participates in the commission of a crime, even though they take no part in the actual criminal offense. For example, in a bank robbery, the person who points the gun at the teller and asks for the money is guilty of armed robbery. However, anyone else directly involved in the commission of the crime, such as the lookout

Lookout

A lookout or look-out is a person on a ship in charge of the observation of the sea for hazards, other ships, land, etc. Lookouts report anything they see and or hear. When reporting contacts, lookouts give information such as, bearing of the object, which way the object is headed, target angles...

 or the getaway car driver, is an accomplice, even though in the absence of an underlying offense keeping a lookout or driving a car would not be an offense.

An accomplice differs from an accessory

Accessory (legal term)

An accessory is a person who assists in the commission of a crime, but who does not actually participate in the commission of the crime as a joint principal...

 in that an accomplice is present at the actual crime, and could be prosecuted even if the main criminal (the principal

Principal (criminal law)

Under criminal law, a principal is any actor who is primarily responsible for a criminal offense. Such an actor is distinguished from others who may also be subject to criminal liability as accomplices, accessories or conspirators....

) is not charged or convicted.