Preparedness is a condition of being completely ready for something, especially some kind of disaster. Your family's preparedness for an approaching hurricane might include an evacuation plan.
The noun preparedness has been around since the 16th century, originally simply meaning "a state of being prepared." That definition is still used today, but it's more common when talking about something potentially devastating, like a war or a natural disaster. If you live on an earthquake fault line, your town's preparedness may consist of emergency shelters and reinforced buildings. A country's military preparedness is its readiness to fight a war or defend itself.