Noun
The quality or state of being rapid; swiftness; celerity; velocity; as, the rapidity of a current; rapidity of speech; rapidity of growth or improvement.
Source: Webster's dictionaryThey look quite promising in the shop, and not entirely without hope when I get them back into my wardrobe. But then, when I put them on they tend to deteriorate with a very strange rapidity and one feels sorry for them. Joyce Grenfell
From that date the abandonment of the older State proceeded with a rapidity never before known, and with it grew the domestic slave trade and the pro-slavery feeling. Henry Charles Carey
Telegraphs are machines for conveying information over extensive lines with great rapidity. Charles Babbage
When public opinion changes, it is with the rapidity of thought. Thomas Jefferson
The military principles of Caesar were those of Hannibal, and those of Hannibal were those of Alexander - to hold his forces in hand, not to be vulnerable at any point, to throw all his forces with rapidity on any given point. Napoleon Bonaparte
the merchant had observed that the marginal utility of daughters decreases with surprising rapidity. Joan Robinson