Pseudodictionary is a dictionary of slang and casual English. Most words have been submitted by users. This is both good and bad: good, because the dictionary is not limited to whatever the editors happen to hear, and bad, because there seems to be minimal control over what the users submit. Just because a new slang expression is used a lot in your homeroom in Harvey Mudd Elementary in Cowflop, Arkansas, doesn't mean it deserves to be given nationwide attention. And what's to prevent submitters from just making up words or expressions they think sound good?
The site owners are also rather politically correct: They won't accept words that are "drug related, overly sexual, describing genitals or body functions, and aren't racist or hateful. we want to keep the site lighthearted and fun for everyone, so words like those won't be added."
Sigh. Lighthearted, fun, and untrue to how English is actually spoken.
I've submitted a few words, but Pseudodictionary lost their CGI guy about six months ago, and no new words were being added for a long time. Apparently they found a new one, because the site recently got a redesign, and they've started clearing their backlog of user-submitted words. In fact, one of the words I suggested was added. Yay! But they still have over 1400 submissions to clear.
When you want to know the meaning of word that is not politically correct, you might have a look at Roger's Profanisaurus, a collection of slang, largely sexual. It's interesting, but seems to be oriented towards British-isms. For example, it doesn't include 'Hawaiian muscle fuck', probably an American expression. It's edited by 'William H. Bollocks', with research by 'Ribena de Farquar-Toss'. Hehe, right, guys. Wizard's Gay Slang Dictionary has a lot of, well, gay slang. Yahoo's Slang Dictionaries page lists a lot of slang dictionaries for parts of the British Empire—Britain, Ireland, Australia, even New Zealand—but very few American slang resources, for some reason. There's SlangSite, but it seems pretty casual, and about as uncontrolled as Pseudodictionary, with users adding anything they want.
And before I leave the subject of dictionaries, I assume everyone is familiar with The Jargon File, an old and famous collection of geek-speak? Very entertaining just to browse through. Less amusing but more useful is WhatIs, a database of computer tech terms. I've used it occasionally to check on the meaning of a term I'd heard of but didn't know the exact meaning of. A helpful tool.
I love words!