[Phil] I never saw it before, until I googled it in a spirit of misunderestimation. The OED has it as an obsolete verb, which I suppose is why an antiquarian map dealer might use it to ornate his prose. But as Caxton writes, "Somtyme ornatynge of wordes maketh the proposycion to be withdrawen fro the trouthe."
It's usually mixed up in some way to even both sides out. Things have quieted down. Dual the A11!
Is the interesting thing about these words simply that they don't appear to have been verbed in the 'normal' way - i.e. by an apparent change in the spelling? After all, it presumably doesn't count in the noun-to-verb category to include the verb "to shelve" since it isn't "to shelf", whereas "to tree" involves no spelling change (although I think some linguists would argue there is a morphological change by virtue of the change of use). In these non-spelling-change cases, it's presumably for some other reason that they appear the same when verbed... You can verb "thick" by spelling it "thicken", whereas "thin" doesn't lend itself to being spelt "thinnen".
[Non-adjective verbings] Saki has an instance of the verb "to sky", meaning the practice of putting the paintings of lesser artists higher up on the gallery wall, above better-regarded work.
Nounish verbings: beach, ship, dog, horse, house, caravan, cup, motor, earwig. "Some to think of it," he umbrella'd, "there aren't many words you can't slip in as a substitute for 'said'."