Bill Watterson once wrote in a Calvin and Hobbes strip: “I realized that the purpose of writing is to inflate weak ideas, obscure poor reasoning, and inhibit clarity.” One of the many ways this purpose is achieved — unconsciously or otherwise — is through the use of weasel words. The term was coined by Stewart Chaplin in a short story published by The Century Magazine in 1900. The character St. John says:
Why, 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 a feather, and not very filling when you’re hungry, but a basketful of them would make quite a show, and would bamboozle the unwary.
The term was popularised in 1916 when Theodore Roosevelt used it in a speech; its profile has grown again recently, and some commentators have extended its original meaning to include clichés, euphemisms, non sequiturs, the passive voice, and vague speech or writing in general. Because several pages would be required to cover all these usages, and because I’m not convinced by the loosely extended definition, I’ll mention just a few prime culprits: clearly, obviously, patently, significantly, plainly, certainly, supposedly, actually, undoubtedly, wholly, and even the humble very.
It is a curious paradox that the use of such intensifiers (also called intensives) seems to have the opposite effect to what is intended. That is, intensifiers can compromise the point being made. A study of their use in appellate briefs (PDF, 334 KB) reports that “as things become less clear, judges tend to use ‘clearly,’ and ‘obviously’ more often.” It’s worth considering why. If a writer’s points are clear, plain and forceful, weasel words are superfluous. If a writer’s points are not clear, plain and forceful, they will not become so with weasel words.
In other words, weasel words will not bridge the gap of persuasion. They can, of course, be used in exemplary ways that do not cast doubt on the writer’s credibility; unfortunately, they seem just as likely to be used to “inflate weak ideas, obscure poor reasoning, and inhibit clarity”, as Calvin put it. I recommend using them sparingly.