Definition of "untanned"

by nature, his manner was not unrefined, his frame slender, and appeared the more so from the broad, untanned frontlet of his brow, tangled over with a disheveled mass of raven curls, throwing a still deeper tinge upon a complexion like that of a shriveled berry.

1857, Herman Melville, chapter XXXVI, in The Confidence-Man: His Masquerade