A swift event or process happens very quickly or without delay.
e.g. Our task is to challenge the UN to make a swift decision...
e.g. The police were swift to act.
The French have acted swiftly and decisively to protect their industries.
The secrecy and swiftness of the invasion shocked and amazed army officers.
Something that is swift moves very quickly.
e.g. With a swift movement, Matthew Jerrold sat upright.
Lenny moved swiftly and silently across the front lawn.
...a swiftly flowing stream.
With incredible swiftness she ran down the passage.
A swift is a small bird with long curved wings.