-fəl adjective
Etymology: Middle English gastful, from gast, gost spirit, ghost + -ful — more at ghost
1. obsolete : full of fear : frightened
the prelate saw their fall with ghastful eyes — John Ozell
2. archaic : giving rise to fear : frightful
this ghastful dream … soon awoke him — John Lane fl 1620
• ghast·ful·ly -fəlē adverb , obsolete