Definition of "significancy"

To break in upon this Sanctuary of Vanity and Ignorance, will be, I ſuppoſe, ſome Service to humane Understanding: Though ſo few are apt to think, they deceive, or are deceived in the Uſe of Words; or that the Language of the Sect they are of, has any Faults in it, which ought to be examined or corrected, that I hope I ſhall be pardon’d, if I have in the Third Book dwelt long on this Subject; and endeavoured to make it ſo plain, that neither the inverateneſs[sic – meaning inveterateness] of the Miſchief, nor the prevalency of the Faſhion, ſhall be any Excuſe for thoſe, who will not take Care about the meaning of their own Words, and will not ſuffer the Significancy of their Expreſſions to be enquired into.

1689 (indicated as 1690), [John Locke], “The Epistle to the Reader”, in An Essay Concerning Humane Understanding. […], London: […] Eliz[abeth] Holt, for Thomas Basset, […], book I

[…] I have added to both of them [language and poetry] in the choice of Words, and Harmony of Numbers which were wanting, […] One is for raking in [Geoffrey] Chaucer (our Engliſh Ennius) for antiquated Words, which are never to be reviv'd, but when Sound or Significancy is wanting in the preſent Language.

1697, Virgil, “Postscript to the Reader”, in John Dryden, transl., The Works of Virgil: Containing His Pastorals, Georgics, and Æneis. […], London: […] Jacob Tonson, […], page 621

The object of rhetoric is persuasion,—of logic, conviction,—of grammar, significancy.

1835, Samuel Taylor Coleridge, edited by Henry Nelson Coleridge, Specimens of the Table Talk of the Late Samuel Taylor Coleridge. In Two Volumes, volume I, London: John Murray, page 207

With this brain I must work, in order to give significancy and value to the few facts which I possess.

1852, Thomas De Quincey, “Sir William Hamilton”, in Hogg's Instructor