unorthodox, a. heterodox.
unpacifiable, a. [implacable], [unappeasable], [unreconcilable].
unpaid, a. outstanding, [payable], [due], unliquidated.
unpardonable, a. inexpiable, [unatonable], irremissible, [unforgivable].
unpassable, a. [impassable].
unpenetrable, a. [impenetrable], [impervious], imperforable.
unpierceable, a. imperforable, [impenetrable].
unplanted, a. [fallow].
unpleasant, a. [disagreeable], [uncongenial].
unplowed, a. [fallow].