adj. & adv.
adj. (ghastlier, ghastliest) 1 horrible, frightful. 2 colloq. objectionable, unpleasant. 3 deathlike, pallid.
adv. in a ghastly or sickly way (ghastly pale). ghastlily adv. ghastliness n.
[ ME gastlich f. obs. gast terrify: gh after ghost ]