unchallenged
adj.not being questioned or criticized by anyone. You use this to describe a situation where no one has tried to prove that something is wrong.
adj.not subject to criticism, opposition, or doubt. Often used to describe a state of being accepted as true or valid without any competing claims.
“The team's record remained unchallenged for five years.”
“The new law was passed without any unchallenged opposition from the local community.”
“For decades, the prevailing theory of the universe's origin remained unchallenged until recent astronomical data provided evidence of a different mechanism.”
“He allowed the president’s lies to go unchallenged.”
“Coburn then doubled the advantage after 50 minutes, taking advantage of poor defending to score unchallenged with a downward header from 10 yards.”
From un- + challenged.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.