demonstrable (adj.)

• absolute
• actual
• apodictic
• apparent
• certain
• checkable
• conclusive
• confirmable
• demonstrated
• evident
• factual
• historical
• incontestable
• incontrovertible
• indisputable
• indubitable
• irrefutable
• manifest
• obvious
• positive
• provable
• real
• self-evident
• supportable
• sustainable
• testable
• unanswerable
• undeniable
• unimpeachable
• unquestionable
• verifiable