Either he or I (is/am/are) to go there.​

the answer is are for sure

1. rude and disrespectful behavior = One must make a distinction however: when dragged into prominence by half poets, the result is not poetry, nor till the poets among us can be "literalists of the imagination"–above insolence and triviality and can present for inspection, "imaginary gardens with real toads in them," shall we have it. . . (from "Poetry" by Marianne Moore) 

This is assuming the bolded word is insolence. Insolence has to do with rude behavior, with someone being disrespectful and not showing appropriate behavior towards someone above their status. Insolence means bad manners.

2. an opening for the passage of steam or liquid = The jar was round upon the ground And tall and of a port in air. (from "Anecdote of the Jar" by Wallace Stevens)

This is assuming the bolded word is port. The word port comes from Latin porta, which means gate, and later from French porte, which means door. So when it was assimilated into English (port), one of its meanings is that it is an opening of some sort. 

3. the feeling that a person or a thing is worthless = Reading it, however, with a perfect contempt for it, one discovers in it after all, a place for the genuine. (from "Poetry" by Marianne Moore)

This is assuming the bolded word is contempt. Contempt refers to scorn, disdain, negative emotions towards someone on the basis that they are not worthy of your consideration. You will probably disregard them as something completely irrelevant.