I'm trying to accurately describe how I feel about a person who acts like they know everything and yet make naive and ignorant arguments. They are somewhat like an adolescent who obtains a bit of knowledge and subsequently acts arrogantly and dismissively towards others. There are aspects of naivete, juvenility, brashness / insolence, arrogance, pretension, and snideness. I want to say intellectual pretentiousness, yet even that sounds too complimentary to me. What do you think?

I also want to express the obnoxiousness of it, and how it is so much more objectionable than just basic ignorance.

Whether it be a few words, a sentence, or a paragraph, any help would truly be appreciated. Thanks!
My father was a wise man.

He told me that written words last forever but spoken words fade.

Why waste your precious time writing something that you may wish you had never put to paper in a few years?

The person you describe sounds as if they merit nothing more that being totally ignored.

Use your talents elsewhere.
I'm sorry, could you elaborate? Do you think I may regret writing this?
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I can't say whether or not you may regret writing the sort of letter you have asked help with - only you are qualified to make that judgement.

I am saying that because English is such a powerful language when it comes to expressing emotions and opinions, authors should consider all eventual consequences of the words they commit to paper.

English is highly surgical in its ability to cut into or dissect a situation. I speak three other languages and English is - by far - the language that is the most precise. The person you describe in your request sounds like someone that may, indeed, need to be enlightened. He (or she) also sounds as if he would take little heed of your opinion.

I am assuming that you intend to sign your name to the letter. Providing him with a written document that he can wave in your face sometime in the future might actually do more harm to you than good to him. If you intend to send the letter anonymously, I can’t help you.

Is it impossible for you to just ignore this person? To look right through them as if they do not exist? I have found this tactic to be much more effective in certain instances than writing a letter.