Definition of "oracular"

In some of the Hebrides they attributed the same oracular power to a large black stone by the sea-shore, which they approached with certain solemnities, and considered the first fancy which came into their own minds, after they did so, to be the undoubted dictate of the tutelar deity of the stone, and, as such, to be, if possible, punctually complied with.

1810, Walter Scott, “(please specify the canto number or page)”, in The Lady of the Lake; […], Edinburgh: […] [James Ballantyne and Co.] for John Ballantyne and Co.; London: Longman, Hurst, Rees, and Orme, and William Miller, (please specify the stanza number)

Ferguson's sin consisted in his oracular 'unmasking' of a 'second-rate sort of society, full of second rate citizens, pursuing comparatively worthless objects.'

2006, Lisa Hill, The Passionate Society: the social, political and moral thought of Adam Ferguson‎

It was one of those dire oracular pronouncements that Marko made from time to time, which were afterwards spread from mouth to mouth among the Serbs.

1963, “Chapter 26”, in Joseph Hitrec, transl., Bosnian Chronicle, New York: Arcade, translation of original by Ivo Andrić, published 1993, page 402

My Lord Chatham, whose wisdom his party in those days used to call superhuman, raised his oracular voice in the House of Peers against the American contest;

1844 January–December, W[illiam] M[akepeace] Thackeray, “The Memoirs of Barry Lyndon, Esq. [The Luck of Barry Lyndon.]”, in Miscellanies: Prose and Verse, volume III, London: Bradbury and Evans, […], published 1856

Nothing offended me but that lisping Miss Haughton, whose every speech is inarticulately oracular.

1754, Horace Walpole, letter to John Chute

This utterance was admirably oracular, being susceptible of cogent quotation by both sides […]

1895, Andrew Dickson White, History of the Warfare of Science with Theology in Christendom