A post by Mark Peters on Visual Thesaurus ("Hiking the Euphemistic Trail") discusses the linguistic consequences of Mark Sanford's recent absence from his duties as governor of the state of South Carolina. As a cover for his time spent in Argentina with a woman other than his wife, he was initially reported to be "hiking the Appalachian Trail." So now, we can look forward to hearing "I was just hiking the Appalachian Trail" whenever someone is up to something they shouldn't be up to.
What's at work here is the creative feature of language; there simply is no definable limit to what humans can do with words, although what we do has to conform to the grammar of our language. In this case, a new idiom has appeared; an idiom is a phrase whose meaning cannot be interpreted using the ordinary meanings of its constituents. Some familiar English idioms include kick the bucket, jump the shark, doggy bag, piece of cake, cut the mustard, and talk turkey.
My question: What do I now tell my wife, family, and friends when I really am off hiking the Appalachian Trail?
The Appalachian Trail, near Hagerstown, MD, August 2006.