I was taught that there were about 350,000 words in English, and a new estimate puts the size of the English vocabulary at 1,022,000 words. So I won't argue that we're in desperate need of new words, but I do wish to recommend a neologism from 1979, from Frederik Pohl's apocalyptic, ambiguously dystopian, beautifully satiric SF novel Jem.
You see, there is an upside to the world of Jem: equality of the sexes. Not so much as we'd demand of a future world nowadays, but not bad for a novel written in 1979 — and mostly better than we're doing in 2012.
Among greater gifts, Pohl gives us in Jem a new term of abuse: prunt. The word is sexual, as a lot of English abuse is, and anatomical, but equal opportunity. It's problematic because it continues the idea that there's something nasty about the body and about sex, but it doesn't put a lot of stress on such pernicious concepts. Mammalian bodies do not have a prunt.
So prunt gets the invective job done, with minimal corruption of people's views of their bodies and such, and without privileging males or females. And it's not a cliché word and one of the dead metaphors George Orwell properly condemns. No, prunt is something new and maybe paradoxical, a word to provoke thought (possibly thoughts of punching you out, but that's a risk of any term of abuse).
Prunt is like unto the "clitopenis" in Ursula K. Le Guin's "Coming of Age in Karhide," but decorously vulgarized: monosyllabic, more ambisexual, not far from four letters, and satisfyingly plosive and aggressive in sound.
It will also get past cybernetic censors designed to stop taboo words.
If Shakespeare can be complimented for the inventive invective in Kent's tirade in King Lear climaxing in calling the craven villain Oswald the "son and heir of a mongrel bitch"; if Gunnery Sergeant Hartman in Full Metal Jacket might be admired for the energy, ingenuity, and downright fecundity of his verbal abuse of recruits — if these be allowed, then let us now praise the introduction of an inclusive, unisex word that doesn't single out women or men or bash gays or other minority groups — but a word that gets the insult job done.
So if you want to spit out a word nasty, brutish, and short — but maybe prudently confusing — I pass along for your use (ta-dum!), prunt! (Save it for special occasions.)