This is the 12689th most frequent Polish word.
niekwestionowany
Undisputed.
The word 'niekwestionowanym' here describes Jan as a leader whose position or authority cannot be challenged by others.
Jan jest niekwestionowanym liderem tej grupy.
Jan is the undisputed leader of this group.
The word 'niekwestionowany' here characterizes the success of the project as obvious and beyond doubt.
To był niekwestionowany sukces tego projektu.
It was an indisputable success of this project.
The word 'niekwestionowany' in this sentence emphasizes that her talent is acknowledged and without dispute.