It means to be totally awesome :)
And what they said ^ :)
courage is not the absence of fear, but the ability to face your fears and overcome
that is what it means, to fight your fears and help others to do so as well
(also raising hell isnt out of the question)
COURAGE: The Ability to overcome your fears.
BRAVERY: The Ability to stay strog through suffering. Like the Longbottoms did.
That's what makes up a Gryffindor.