As an adjective aghast
is terrified; struck with amazement; showing signs of terror or horror.
As a noun dismay is
a sudden or complete loss of courage and firmness in the face of trouble or danger; overwhelming and disabling terror; a sinking of the spirits; consternation.
As a verb dismay is
to disable with alarm or apprehensions; to depress the spirits or courage of; to deprive of firmness and energy through fear; to daunt; to appall; to terrify.