1. (adjective) not counterfeit or copied

• authentic
• bona fide
• veritable

1. (adjective) incapable of being questioned

• acknowledged
• beyond doubt
• indubitable
• for sure
• mathematical
• unimpeachable

2. (adjective) not counterfeit or copied

• echt
• genuine

3. (adjective) not open to question

• unambiguous
• unequivocal
• univocal

1. (adjective) incapable of being questioned

• incontestable
• incontestible
• undeniable

1. (adjective) incapable of being questioned

• indisputability
• indisputability
• indubitability
• indubitability
• unquestionability
• unquestionability
• unquestionableness
• unquestionableness

2. (adjective) not counterfeit or copied

• authenticity
• genuineness
• legitimacy
• indisputability
• indubitability
• unquestionability
• unquestionableness

3. (adjective) not open to question

• indisputability
• indubitability
• unquestionability
• unquestionableness

1. (adjective) incapable of being questioned

• questionable