Definition of "unsunned"

[…] I thought herAs chaste as unsunn’d snow.

1611 April (first recorded performance), William Shakespeare, “The Tragedie of Cymbeline”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene v]

[…] but day by dayLife brings you nothing new or bright:The bloom of boyhood dies away;And youth, unsunned by youth’s delight,Yields place to manhood tame and drear—Blank year succeeding to blank year.

1878, John Addington Symonds, “In the Inn at Berchtesgaden”, in Many Moods: A Volume of Verse‎, London: Smith, Elder & Co., page 41

Presently after, he sat on one side of his own hearth, with Mr. Guest, his head clerk, upon the other, and midway between, at a nicely calculated distance from the fire, a bottle of a particular old wine that had long dwelt unsunned in the foundations of his house.

1886 January 5, Robert Louis Stevenson, Strange Case of Dr Jekyll and Mr Hyde, London: Longmans, Green, and Co.

This portion of basement was uncemented, low-ceiled, earthy, unsunned.

1944, Emily Carr, “Basement”, in The House of All Sorts‎