Where does “ghastfull” come from?

ghastfull (English) comes from English ghast, from English gaſt, from German gaſt, from Middle High German gast, from Old High German gaſt, from Proto-West Germanic *gasti, from Proto-Germanic gastiz, from Proto-Indo-European gʰóstis — Derives abstract/action nouns from verb roots.

Ancestry of “ghastfull”, step by step

StepLanguageWordMeaning
1EnglishghastAlternative form of gast; Having a ghastly...
2EnglishgaſtTo frighten
3Germangaſtguest
4Middle High Germangast
5Old High Germangaſtguest
6Proto-West Germanic*gastiguest
7Proto-Germanicgastizstranger, guest
8Proto-Indo-Europeangʰóstisstranger, host
9Proto-Indo-European-tisDerives abstract/action nouns from verb roots
Every word from Proto-Indo-European -tis