Adjective : a plausible excuse; a plausible plot. ,a plausible commentator.    From Dictionary.com. 

There is the plausibleness of it, the temptation of it.    From Wordnik.com.  [Captivity] Reference

And the plausibleness of it made it the more dangerous.    From Wordnik.com.  [Commentary on the Whole Bible Volume I (Genesis to Deuteronomy)] Reference

There was a certain plausibleness in this reasoning which curbed.    From Wordnik.com.  [The Captain of the Kansas] Reference

It is plain therefore, that nothing under the name of a divine revelation can with any, the least plausibleness be brought into competition with this book.    From Wordnik.com.  [The Whole Works of the Rev. John Howe, M.A. with a Memoir of the Author. Vol. VI.] Reference

He valued himself too much, as the Pharisees did, upon the plausibleness of his profession before men, and was proud of that, which spoiled the acceptableness of it.    From Wordnik.com.  [Commentary on the Whole Bible Volume V (Matthew to John)] Reference

In spite of the visions of their annual feasts which this gastronomic simile must have called up in their minds, the alumni refused to be seduced by its plausibleness.    From Wordnik.com.  [History of the University of Virginia, 1819-1919] Reference

If a man drew his wife by lot, or by any other method over which neither he nor she has any control, as in the case of parents, perhaps he might with some plausibleness contend that he owed her certain limited deferences and reserves, just as we admit that he may owe them to his parents.    From Wordnik.com.  [On Compromise] Reference

I found it contain a greater number of circumstances than could have been expected in this species of publication, I was equalled to the most notorious housebreaker in the art of penetrating through walls and doors, and to the most accomplished swindler in plausibleness, duplicity, and disguise.    From Wordnik.com.  [Caleb Williams Or Things as They Are] Reference