Definition of "incognito"

The Scepticks think 'twas long ago, / Since Gods came down Incognito; / To ſee who were their Friends or Foes, / And how our Actions fell or roſe.

1703, Mat[thew] Prior, “The Ladle”, in Poems on Several Occasions, 2nd edition, London: […] Jacob Tonson […], published 1709, stanza 1, page 125

"But you can understand," said our strange visitor, sitting down once more and passing his hand over his high white forehead, "you can understand that I am not accustomed to doing such business in my own person. Yet the matter was so delicate that I could not confide it to an agent without putting myself in his power. I have come incognito from Prague for the purpose of consulting you."

1891 June 25, A[rthur] Conan Doyle, “Adventures of Sherlock Holmes. Adventure I.—A Scandal in Bohemia.”, in Geo[rge] Newnes, editor, The Strand Magazine: An Illustrated Monthly, volume II, London: George Newnes, Limited, […], published July 1891, page 65, column 2

The prince royal of Prussia came thither incognito.

1709 May 30 (Gregorian calendar), Isaac Bickerstaff [et al., pseudonyms; Richard Steele et al.], “Thursday, May 19, 1709”, in The Tatler, number 17; republished in [Richard Steele], editor, The Tatler, […], London stereotype edition, volume I, London: I. Walker and Co.; […], 1822

His incognito was endangered.

1814 July 7, [Walter Scott], Waverley; […], volumes (please specify |volume=I to III), Edinburgh: […] James Ballantyne and Co. for Archibald Constable and Co.; London: Longman, Hurst, Rees, Orme, and Brown

It contained a letter from the King himself, craving hospitality for a few days, as his mother was about to visit England, and to take up with Lord Avonleigh her residence at the Castle. A slight incognito would be preserved, and as little form and ceremony expected as was possible.

1834, L[etitia] E[lizabeth] L[andon], chapter XX, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), page 169