It’s a word I haven’t heard in years: preventative. Is it an incorrect adjectival form of prevent? Not really. It’s considered an alternate form, though not preferred by most authorities. In fact, preventive is far more popular in the U.S. than preventative, which is as popular as preventive in the U.K. So, when I read this on the Yahoo! front page, did I think the writer made a horrible mistake?
Kinda, though it’s not the word I would chose. (I tend to favor the dictionary’s preferred spelling of words over the acceptable spellings.) But then I read this on Daily Writing Tips and it was enough to solidify my preference for preventive:
“The most respected publications favor preventive, while preventative is more likely to appear in print and online sources with less rigorous editorial standards. That’s a good enough reason to favor preventive.”