1. To do or move with great speed. English = (be) quick, (be) sudden; rush.
2. To need to be done or dealt with as soon as possible. English = (be) urgent.
1. Used alone to tell someone to do something with greater speed, usually because you are waiting for them and/or there is not much time before something else happens. English = 'Quickly!', 'Hurry up!'
1. Used immediately next to a verb to mean the action happens with great speed. English = quickly.
2. Used to introduce a sentence to mean the action happens with some surprise and speed. English = suddenly, all of a sudden.