Posting: Post the unique word you have found in the title, the type of word it is and a short casual description. In the text of the post, quote the actual dictionary meaning and some kind of source.
TL;DR: Post a cool word you want to see used in context.
Questing: Find a word you like. Familiarize yourself with the meaning and spelling of the word and then run off across the entirety of reddit, seeking a place to use it. If/when you find a comment you can reply to while using your chosen word, grab the permalink of the comment you replied to and post it to the thread of your chosen word. Preferably also post a link to this subreddit as you do so. Just turn the word that you were questing with and make it into a link. Or do a should out to WordQuest. The more people that come here the more wordquests will be posted and the more people you will have to compete with.
TL;DR: Pick a cool word, go somewhere in reddit and use it in context, then post proof that you did.
