• contentious, controversial, disputed, vexed
• arguable, debatable, disputable, impugnable
• to argue, to contend, to contest, to debate, to dispute
• beyond dispute, incontestable, incontrovertible, unarguable, uncontroversial, uncontrovertible, undisputed, undoubted
• beyond doubt, beyond question, indisputably
• to impugn the character of a witness
• to argue, to canvass, to debate, to discuss, to dispute, to moot, to talk over
• to let go unchallenged, to let pass unchallenged