Definition of unobtainium in English:

unobtainium

(also unobtanium)

Pronunciation /ˌənəbˈtānēəm/ /ˌənəbˈteɪniəm/

noun

informal
  • A highly desirable material that is hypothetical, scientifically impossible, extremely rare, costly, or fictional, or has some of these properties in combination.

    • ‘what type of cabling are we talking about, steel, composite, unobtainium?’
    • ‘Indeed, the claims made for this technology sometimes make it sound like the legendary aerospace material ‘unobtainium.’’
    • ‘Veteran space industry analyst John Pike, director of GlobalSecurity.org, likes to joke that the required substance should be dubbed ‘unobtainium.’’
    • ‘But the Japanese 8mm Nambu cartridge might as well have been made of unobtainium.’
    • ‘‘It's made of carbon, aluminium, titanium,’ he revealed, before, perhaps sensing that his audience wasn't suitably impressed, adding: ‘and, er, unobtainium.’’