Indefeasible

adj. impossible to cancel, cannot be voided or annulled

Defeasible reasoning is the study of forms of reasoning that, while convincing, are not as formal and rigorous as deductive reasoning. It has been discussed in philosophy and, more recently, in artificial intelligence.Other alternatives to deductive reasoning include inductive reasoning and retroductive reasoning. These are not traditionally covered by most uses of the term "defeasible reasoning".
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Adjective
1. not liable to being annulled or voided or undone; "an indefeasible right to freedom"; "an indefeasible claim to the title"
(antonym) defeasible
(similar) unforfeitable, inalienable

(a.)
Not to be defeated; not defeasible; incapable of being annulled or made void; as, an indefeasible or title.
  

A right or title in property that cannot be made void, defeated or canceled by any past event, error or omission in the title. - (read more on Indefeasible)