Wicca-derived modern neopagan slang terms like “newbie” and “getting thwapped” have absolutely no place in even moderately reconstructionist pagan religions.
“Newbie” is a term implying resentment towards beginners. It’s appropriate in something like online gaming, where beginners can be annoying and in the way. Whether or not it’s appropriate in Wicca or other witchcraft practice is none of my business, since I’m not a Wiccan or any other kind of witch. But in [recon] polytheist faiths, that kind of attitude towards new believers makes no sense whatsoever. We should be embracing, welcoming, and guiding new believers, not resenting them and being annoyed at them. Why on earth would we want to discourage people from coming back around to the gods of their ancestors? Sure, just like new believers in any faith, their (our) heads are probably full of leftover ideas from wherever they came from, but the response there should be gentle (or firm, as the case may be) correction, not personal resentment. Direct your ire toward the religion(s) that gave them unhelpful ideas, not toward them for having them. New believers are not in the way; they are an essential part of a living, thriving faith community.
“Being thwapped” is a flippant and disrespectful term for a powerful and sacred revelatory mystical experience. It stems from an casual attitude towards the gods that is born from neopagan beliefs about the nature of divinity that have no place in a truly polytheistic (or any kind of true theistic) faith. But even if you believe that the gods are mere psychological archetypes, they still are potent and powerful archetypes that should be honored and respected. Being casual about them is dangerously disrespectful, if you believe they actually exist in any real sense.
Between the lore we have from the ancients and analogous modern living polytheist faiths we have plenty of vocabulary–specialized, tested, specific vocabulary that properly expresses what we are trying to say the way we should be saying it. Relying on modern neopagan slang to define our spiritual lives essentially allows modern neopaganism to set the terms, and it undermines many of the core concepts of our faiths.
Sailing to Byzantium 
I haven’t heard either term used in a Wiccan context – the ones I’ve been hanging out with lately are nothing but welcoming to newcomers. The same holds true just about any real-life (as opposed to Internet-only) Pagan group of any stripe that I’ve been part of – people are generally really nice. It’s the online folks who tend to play rough, and in my experience it’s the online recon or “traditionalist” types who can be the nastiest to newcomers or to anyone who practices differently.
I agree that people who are still seeking and investigating new paths ought to be welcomed and treated with respect, and “newbie” probably isn’t the nicest term in the world, but how is this “Wicca-derived”? In my experience, Wiccans are eager and happy to share their path with anyone who is genuinely and respectfully interested. Maybe you’ve met some different Wiccans.
I find that using flippant terms to talk about very profound experiences usually stems from discomfort in talking about these things – it’s not that the speaker is taking the experience lightly, but he or she doesn’t really know how to talk about it or is afraid of admitting how intense the experience really was. There’s a tension or insecurity there – if I heard someone say that he had been “thwapped” by a deity, my response would be to take that very seriously indeed and (gently) invite the speaker to talk about it in deeper terms. It would be nice if that tension could be skipped and we could get to the serious bit sooner, but some people are really uncomfortable talking about these things and a bit of compassion goes a long way in such conversations.
The term us imported from the wider neopaganism community, which is dominated by Wicca and New Ageism. They may be plenty friendly towards “newbies,” but the term implies disdain. And, simply put, it’s a stupid word.
“Noob” or “n00b” (as it was first coined as) is the resentful term. It is a derivative of the word “newbie”, indicating that someone one is acting like they are new, yet they are most likely not, and generally being an asshat about things.
Just wanted to point that out. ^^ I do agree with your assessment of “thwapped” however.
I agree with your assesment Kullervo.
I’ve ranted on the same things many times over at my blog. The terms are derogatory and dismissive. I’d put “fluffbunny” in there as well. It helps nothing and only serves to make the user feel superior.