problematical

at issue borderline chancy clear as dishwater clouded cryptic doubtful dubious dubitable enigmatic enigmatical equivocal in doubt in question inconclusive indecisive indefinite indeterminate inexplicit muddy obscure opaque problematic puzzling questionable tenebrous uncertain unclear unintelligible unsure vague

arguable between rock and hard place between sixes and sevens betwixt and between bone of contention borderline chancy contestable contested disputable doubtful dubious exceptionable iffy in dispute moot mootable open to question problematic questionable the jury's out touch and go uncertain undecided unsettled up for discussion