Courage is an attribute that Tropican citizens have. It determines how likely a particular citizen is to become a rebel if they become too unhappy. It also determines whether a citizen is brave enough to ride a high speed Ferris Wheel.
It's possible that citizens and soldiers with high courage are less likely to flee in battle.
Children who attend Grade Schools that provide Obedience Training will have reduced courage when they become adults.
Courage can be viewed for each individual citizen in the Skills screen of the Citizen's Information Page