> as lemmas
uncrackable
uncrackable adj. 
/(ˌ)ʌŋˈkrakəbl/,
Brit. /(ˌ)ʌnˈkrakəbl/
, /(ˌ)ʌnˈkrakəbl//(ˌ)ʌŋˈkrakəbl/U.S. /ˌənˈkrækəb(ə)l/
/ˌənˈkrækəb(ə)l/ΚΠ
1786 H. Walpole Let. 16 Jan. in Corr. (1965) XXXIII. 508 You might have made me a little amends by sending me the prologue..instead of a charade which I shall never guess. In revenge here is one, which I hope you will all find as uncrackable.
1872 Preacher's Lantern 2 547 A peach, all lusciousness without, and a hard uncrackable stone within.
1921 Toys & Novelties Feb. 170/1 (heading) Uncrackable enameled toys.
2017 Arbroath Herald (Nexis) 7 Feb. Use a unique, uncrackable password for all important accounts.
<
as lemmas