also gabbey and gabby, subs. (common).A fool; a babbler; a boor. Ici. gapi = a foolish person, from gapa = to gape.
1811. GROSE and CLARKE, Lexicon Balatronicum, s.v.
1856. T. HUGHES, Tom Browns School-days, pt. I, ch. iii. Two boys, who stopped close by him, and one of whom, a fat GABY of a fellow, pointed at him and called him young mammy-sick.
1859. H. KINGSLEY, Recollections of Geoffry Hamlyn, ch. ix. Dont stand laughing there like a great GABY.
1875. OUIDA, Signa, vol. I., ch. iv., p. 47. You have never dried your clothes, Bruno, said his sister-in-law. What a GABY a man is without a wife.