What is that which has a dark, lowering, or threatening aspect; that which temporarily overshadows, obscures, or depresses; as, a cloud of sorrow; a cloud of war; a cloud upon the intellect called?

cloud — That which has a dark, lowering, or threatening aspect; that which temporarily overshadows, obscures, or depresses; as, a cloud of sorrow; a cloud of war; a cloud upon the intellect. (Webster's 1913.)

Sources