What does aghast mean?
The definition of aghast
A*ghast”, v. t.
See Agast, v. t. [Obs.]
A*ghast”, a & p. p.
Etym: [OE. agast, agasted, p. p. of agasten to terrify, fr. AS. pref. a- (cf. Goth. us-, G. er-, orig. meaning out) + g to terrify, torment: cf. Goth. usgaisjan to terrify, primitively to fix, to root to the spot with terror; akin to L. 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.