Definition of "yellowness"

[…] at least there would be no harm in getting a few bottles of “stuff” from him, since if these proved useless it would still be possible to return to the Purifying Pills, which kept you alive, if they did not remove the yellowness.

1872, George Eliot, Middlemarch‎, London: William Blackwood & Sons, Volume III, Book V, Chapter 45, p. 25

[…] lemonade of a yellowness sufficient to convince the most inveterate pessimist of the presence of the lemon.

1924, Herbert Jenkins, The Bindles on the Rocks, London: Herbert Jenkins, Chapter VI, Part II

My humour shall not cool: I will incense Page to deal with poison; I will possess him with yellowness, for the revolt of mine is dangerous: that is my true humour.

c. 1597 (date written), William Shakespeare, “The Merry Wiues of Windsor”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene iii]

The vndiscreet carriage of some lasciuious gallant […] by his often frequenting of an house, and bold vnseemly gestures, may make a breach, and by his ouer familiarity, if he be inclined to yellownesse, colour him quite out.

1624, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy: […], 2nd edition, Oxford, Oxfordshire: Printed by John Lichfield and James Short, for Henry Cripps, partition 3, section 3, member 1, subsection 2, page 680