www.alphadictionary.com

Inspired by the appearance of "shellac".

Like shellac, a finishing agent, but one that isn't compromised by water, thus is suitable for use in protecting wood surfaces on boats. (And floors and furniture.)

Also like shellac, it can be used as a verb, in this case to apply the liquid to the surface. And figuratively, as in "the unvarnished truth".

Fun coincidence that a word that can mean specious gloss or pretense may have its roots in the former name of Bengasi (Benghazi).

Odd, too, that we have the 'unvarnished truth', but not the other way around.