ghastful
Causing fear; terrifying.
archaic
Very desolate was that valley, having a dark aspect and a ghastful, such as a man might look for in the infernal glens of Pyriphlegethon or Acheron.
Terrified, frightened.
archaic
"The dreadful Stains of Murther on the Face, "That all may ſhun thy Crimes and Fate. — He ſaid, The Caitiff heard, with ghaſtful Looks he fled.
Th' Almighty anſwers — "I my ſelf will place
Where it comes from
From Middle English gastful, equivalent to ghast + -ful. See ghastly.
Adapted from the Wiktionary entry ghastful (CC BY-SA 4.0).