Webster's Revised Unabridged Dictionary · 1913

Aghast

Aghast ({not transcribed}) , transitive verb

See Agast, transitive verb [Obsolete]

Aghast ({not transcribed}) , adjective and past participle

[Old English agast, agasted, past participle of agasten to terrify, from Anglo-Saxon pref. ā- (compare Gothic us-, German er-, orig. meaning out) + gastan to terrify, torment: compare Gothic usgaisjan to terrify, primitively to fix, to root to the spot with terror; akin to Latin haerere to stick fast, cling. See Gaze, Hesitate.]

Terrified; struck with amazement; showing signs of terror or horror.
Aghast he waked; and, starting from his bed, Cold sweat in clammy drops his limbs o'erspread. — Dryden
The commissioners read and stood aghast. — Macaulay