unobtainable

a. 难获得的

unmindful, unmistakable, unmistakably, unmitigated, unmoved, unmoving, unnatural, unnaturally, unnecessarily, unnecessary, unnerve, unnerving, unnoteworthy, unnoticed, unnumbered, UNO, unobjectionable, unobservable, unobserved, unobstructed, unobtrusive, unobtrusively, unoccupied, unofficial, unofficially, unoriginal, unorthodox, unorthodoxy, unpack, unpaid, unpalatable, unpalatably, unparalleled, unparliamentary, unpaved, unpick, unplaced, unplanned, unplayable, unpleasant,