Don Watson has a new book called Watson’s Dictionary of Weasel Words, Contemporary Clichés, Cant and Management Jargon. I don’t know if it’s any good but the image of a weasel sucking out the contents of an egg while leaving the shell intact has always appealed to me.
According to Stewart Chaplin weasel words:
…are words that suck all the life out of the words next to them, just as a weasel sucks an egg and leaves the shell. If you heft the egg afterward it’s as light as feather, and not very filling when you’re hungry; but a basketful of them would make quite a show and would bamboozle the unwary.
You can have universal training, or you can have voluntary training, but when you use the voluntary to qualify the word universal, you are using a weasel word; it has sucked all the meaning out of universal. The words flatly contradict each other.
William Saffire credits William Shakespeare with originating the metaphor. In As You Like It Jaques urges Lord Amiens to continue singing by saying: "I can suck melancholy out of a song, as a weasel sucks eggs." Other commentators refer to another of Shakespeare’s weasel references in Henry V "For once the eagle England being in prey, To her unguarded nest the weasel Scot Comes sneaking, and so sucks her princely eggs".
The Austrian economist Friedrich Hayek referred to Mario Pei’s book Weasel Words: The Art of Saying What You Don’t Mean when he argued that the word ‘social’ tended to suck the meaning out of any word it was placed next to. He likened ‘social justice’ to ‘people’s democracy.’
But the trouble with images like our egg sucking weasels is that they are often grounded in folklore rather than science. Apparently weasels have a lot of trouble sucking anything.