Sophistry is an art of arguing where the purpose of discussion is not about Finding the locus of Truth, doing the justice, exploring the morality, et al.
In Sophistry, the sole motto of involving in an argument is to win it away ,by any means, hook or crook.
In ancient Greece, the distractors of Aristotle were called as Sophist. Mind it that in his times,Aristotle was not so much a revered person as he become later in history. People despised Aristotle for asking too many questions, being highly judgemental, and behaving finicky. Nobody could easily win arguments against Aristotle.
Then came the Sophist people. It is not exactly known if the word Sophist came from some particular person, but now the word is used as a Collective noun. These are people whom even Aristotle had begun to avoid arguing with,for they had developed range of Arguments by which they could defeat anything and anybody at their will. Aristotle discovered the lack of Universality in their arguments, and knew that the Sophists had build bias of both kinds -good and bad-- for everything which could be argued. Thus, the Sophist were able to switch side of goodness, during an argument, about everything easily at their choosing, which helped them defeat their opponents. The lack of Universality could be realized if one were to take a continued application of their arguments in a similar case else where the wrongs were so much apparent. One would find that he could still defend the wrongs using the arguments of the sophist.
Thus, this style of confused arguments came to be known as Sophistry.
In our times, the BJP,the RSS and their likes are doing the Sophistry.
One should the lack of Universality of the arguments of the BJP guys.