All warfare is based on deception. Hence, when able to attack, we must seem unable; when using our forces, we must seem inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near.
Sun Tzu, 孙子兵法 Sunzi Bingfa (The Art of War)
Acerbity [əˈsɜːbɪtɪ] 