Inappealable is a word that means a verdict or decision that cannot be challenged or reversed. Some synonyms for this word include irrevocable, unalterable, final, conclusive, definite, and decisive. Other words that can be used to describe an inappealable decision might include unassailable, unavoidable, or inevitable, suggesting that the outcome was always going to be a foregone conclusion. While the word inappealable can often be used in legal contexts, it can also be used more generally to describe any decision or outcome that is considered to be final and conclusive.