From Wiktionary, the free dictionary
From un- + admitted.
unadmitted (not comparable)
- Not having been admitted.
2009 May 30, Lynda Hurst, “Why we should start worrying and learn to fear the bomb again”, in Toronto Star[1]:And Israel's (unadmitted) stockpile of 200 warheads is seen as the prime driver of Iran's move into the nuclear arena.