If you are aghast, you feel or look shocked by something you have just seen or found out — the kind of shock that stops you for a moment, as if you cannot quite believe it. It is stronger than surprised and quieter than angry. Bad news can leave you aghast; a cruel joke can leave a room aghast. It is an adjective, and we usually say aghast at something. It is a little old-fashioned and story-like, so you will meet it in books more than in a text message. Though actually, the face is part of the meaning: people who are aghast often look it — stuck to the spot, a bit frozen.