ungettableadj.
Etymology: Previous versions of the OED give the stress as: unˈgettable.
the mind > possession > acquisition > [adjective] > unobtainable
1554 in J. Stuart (1844) I. 282 [If the sum is] vngettable of his office, thai oblissis thame..to releiff him therof.
This entry has not yet been fully updated (first published 1924; most recently modified version published online June 2019).