A more thorough explanation:

in periculo constitutus

When someone is in periculo constitutus, they are in danger.

• During the hurricane, many people were in periculo constitutus.
• The soldiers knew they were in periculo constitutus when they heard the enemy approaching.

The examples show situations where people are in danger. In the first example, people are in danger because of a natural disaster. In the second example, soldiers are in danger because of an enemy attack. Both situations illustrate the definition of in periculo constitutus.