Antecedent
That which goes before, especially the word, phrase, or clause to which a pronoun refers. In the sentence, "The witches cast their spells," the antecedent of the pronoun "their" is the noun "witches."
A faction is defined as a group of people with the same interest. According to Madison, the danger that a faction poses to good government is that it acts in its own interest, not the people's interest. What is bad about a faction is that, it will try to get what they want even if it hurts others. Hope this answer helps.
Picnic. frivolity is something that is unnesasary/enjoyable.