Adjective : The law students were an unusually argumentative group. ,an argumentative attitude toward political issues.    From Dictionary.com. 

These answers are offered in an unargumentative way, even where the questions are still in debate among scholars.    From Wordnik.com.  [The Life of Jesus of Nazareth] Reference

She would learn to be docile and unargumentative, for those two qualities seemed to be high on her husband's list of duties.    From Wordnik.com.  [Gentle Warrior]

'It might be just because every country has one, that the one in Johannesburg is not news,' Conrad murmured, in a tone a little too carefully unargumentative.    From Wordnik.com.  [Smokescreen]

Lady Bryan who was sensitive to her charge's willful ways and was curbing them with gentle firmness had, as a reward for dutiful and unargumentative behavior over the previous week, invited a select party to celebrate with the household.    From Wordnik.com.  [This Scepter'd Isle]

How delightfully companionable she could be, he thought; so responsive, so discriminating and unargumentative.    From Wordnik.com.  [The Sign of the Spider] Reference

Without a doubt, these are some of the finest, most upstanding, dependable, unargumentative folks that grace our land.    From Wordnik.com.  [The Daily News - News] Reference

But nothing came to her save the memory of the cold, wet, unargumentative cry of the redshanks that she had heard on the marshes.    From Wordnik.com.  [The Judge] Reference

Mr. Lecky proceeds to some questionable views concerning the evidences of witchcraft, which seem to be irreconcilable even with his own remarks later on; but they lead him to the statement, thoroughly made out by his historical survey, that “movement was mainly silent, unargumentative, and insensible; that men came gradually to disbelieve in witchcraft, because they came gradually to look upon it as absurd; and that this new tone of thought appeared, first of all, in those who were least subject to theological influences, and soon spread through the educated laity, and, last of all, took possession of the clergy.”.    From Wordnik.com.  [The Essays of "George Eliot" Complete] Reference