Having just made a post of words using the prefix "un-" in Joyces Ulysses, I thought it would be interesting to see the unusual/unexpected un- prefixed words in Noah Webster's classic 1828 An American Dictionary of the English Language. It turns out that the created and unusual un-words in Joyce bear a similarity-in-strangeness and the unexpected in the Webster book. Basically, "un-" is a negative prefix, creating (mostly in adjectives) reversal, release, removal. It is distinct from the "non-'" stem, and in some instances understood a little better (in some examples) than the "in-" stem.
There are some fantastic examples of words that become quite something else in the modern eye: beautiful words like "unepitaphed" seem to want to mean that an epitaph would be removed, altered in some way, which is an interesting thought (!), but all it meant in Webster's hand was to be a grave without an epitaph. "Unbearded" too--all it means is to be without a beard,, and not to have a beard removed in some way. "Unextinct"! A wonderful word that brings visions of resurrection, but it means just to be not-extinct, which is still a little odd.
And so I have chosen a few examples of words that might as well have been chosen for their color, or musicality, or potential interpretations than anything else, though basically I like the idea of what the words could become.
An Alphabet of Un-, 1828
A. Unaccomplishment, unalmsed, unamazed, unappalled, unanswerableness, unartificial
B. Unbar, unbearded, unbeget (as a verb! found in Drden, "to deprive of existence"), unbit, unbenighted ("never being visited by dark"), unbestarred, unblameableness.
C. Incentrical, unchristianize, uncompact, uncounterfeit, uincommencement.
D. Undeaf, undefaced, undeceiver, undevout, undisappointed, undreaded.
E. Uneclipsed, unepitaphed, unexistent, unextinct.
F. Unfinisher, unfleshed.
G. Ungalled, ungod.
H. Unhale, unhollow, unhumble, unhuman, unharrassed, unheeding.
I. Unindustriousness, uniradiated, unirriating.
J. Unjudged. (A shallow entry with only ten examples in a 30-page "un" section.)
K. Unkennel, unking, unkissed.
L. Unlavish, unlearn, unleissured, unlicked, unliquified.
M. Unmake ("to deprive the form and qualities which constitute what a thing is"), unmeetness, unmingle.
N. Unnaturalize. (Only 26 words in this category.)
P. Unparadise, unpeople, unpenal.
Q. Unqualitied (The Unqualitied Man would not sound nearly so go as the Robert Musil's original The Man Without Qualities), unquerrable, unquickened.
R. Unremembering, unrepugnant, unriddle, unring.
S. Unscaly, unscholastic, unscriptual, unsepulchered, unsmooth.
T. Untasted, untent, unthread.
U. Ununiform (another skimpy section, with just nine examples).
V. Unvaluable, unverdant, unvoweled.
X. No examples/entries.
Y. Another scant section, the best here being Unyoke.
Z. No examples.
I would say that there are 3,000 words in the "un-" section of Websters, and that fully a fifth of them give you something to think about...maybe a little more.
[This post's artwork is a remanufacturing of a cover from Astounding Science Fiction 1947, with the art by Alejandro for the novelette 'AESOP' by Clifford D. Simak.]