Definition of "doubleness"

And of Zabulon that went out to the battayle and proceded forth to the war, with all maner of instrumentes of war fyftie M. that were prepared to the war, without any doublenesse of herte.

1540, Great Bible, 1 Chronicles 12 [verse 33]

If you think well to carry this as you may, the doubleness of the benefit defends the deceit from reproof.

c. 1603–1604 (date written), William Shakespeare, “Measure for Measure”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act III, scene i]

I only know myself as a human entity; the scene, so to speak, of thoughts and affections; and am sensible of a certain doubleness by which I can stand as remote from myself as from another. However intense my experience, I am conscious of the presence and criticism of a part of me, which, as it were, is not a part of me, but spectator, sharing no experience, but taking note of it;

1854, Henry David Thoreau, “Solitude”, in Walden‎, Boston: Ticknor and Fields, page 146

It was easy for him, when he saw the straight march of his school, the old section taller and wider and brighter than the new wing, and the new wing following in its narrow dark doubleness, to think of boxcars.

1983, Cynthia Ozick, The Cannibal Galaxy‎, New York: Knopf, page 17

But if it be a vice to coulour craftinesse, subtile practises, doublenesse and hollow behauiour, with a cloke of pollicie, amitie and wisedome, then are Comineus and his companie to be reputed vicious.

1577, William Harrison, “[An Historicall Description of the Islande of Britayne, [….] 14.]”, in The Firste Volume of the Chronicles of England, Scotlande, and Irelande […], volume I, London: […] [Henry Bynneman] for Iohn Harrison, folio 39, recto, column 1

It is clear to you, I hope, that Stephen was not a hypocrite—capable of deliberate doubleness for a selfish end; […]

1860, George Eliot [pseudonym; Mary Ann Evans], “Charity in Full-dress”, in The Mill on the Floss […], volume III, Edinburgh, London: William Blackwood and Sons, book VI (The Great Temptation), page 141

I plummeted down [the ski hill] past the zigzaggers, the students, the experts, through year after year of doubleness and smiles and compromise, into my own past.

1963, Sylvia Plath, chapter 8, in The Bell Jar‎, New York: Bantam, published 1972, page 79