What it means to be strong

Is it the smart mouth, wise cracks, or flippant attitude that makes someone strong? Is it possible all of that attitude is just a mask to hide the fear and insecurity inside?

Is it the courage to charge headlong into danger, the knowledge of how to maim and kill, or the blind dedication to the cause that makes someone strong? Could all of that be a shield to hide past failures or the inability to refuse any request?

In other words, what makes someone strong? What traits do readers find and th...