Synonyms for Unanswerable:

adj.

•final (adjective)
definite.
•irrefutable (adjective)
incontestable.
•undeniable (adjective)
true.
•valid (adjective)
authentic.

n.

firm, factual, true, realistic, definitely, definite, objective, authentic. Rapid-fire, unasked, unanswered, interrogative, loaded, open-ended. •unanswerable (noun)
incontestable, incontestible.

Other synonyms:

open-ended, unanswered. interrogative, loaded. •Other relevant words:
incontestable, factual, interrogative, open-ended, loaded.