(1):

(superl.) Ready and quick to act as occasion demands; meeting requirements readily; not slow, dilatory, or hesitating in decision or action; responding on the instant; immediate; as, prompt in obedience or compliance; - said of persons.

(2):

(superl.) Done or rendered quickly, readily, or immediately; given without delay or hesitation; - said of conduct; as, prompt assistance.

(3):

(superl.) Easy; unobstructed.