Bonnie Lewellyn, of Hayward, Calif., writes, "In recent months a puzzling word has reared its head once again: surveil. When I first heard it used, a few years ago, I assumed that the speaker was simply coining a new form of the word surveillance, as in 'We set up a team to surveil the suspect's house.' The correct usage, I assumed, would be 'We set up a team to survey the suspect's house.' I see, however, that Merriam-Webster's Collegiate Dictionary accepts the word surveil as a 'back-formation' of surveillance. Are there any other back-formation words in common usage, and are they considered acceptable in standard English?"
Yes, indeed. Back-formations are newer, shorter words created by stripping away affixes (usually endings) from words that entered English with their affixes firmly attached. For instance, baby-sitter came to us in that form, and the verb baby-sit was derived from it. The verb diagnose is derived from diagnosis, donate from donation, and reminisce from reminiscence. Surveillance, of course, entered English from French, about two centuries ago, whereas the earliest citation for surveil known to Webster's Collegiate's lexicographers is from 1949.
Your reaction to surveil is fairly typical of the response people have to a back-formation they aren't used to seeing: they don't quite believe that the thing is a proper word. But surveil deserves to be a word, it seems to me, because survey threatens to mean a technique of social science or, more likely, land measurement (for instance, here's a recent citation from The Philadelphia Inquirer: "One commando killed a soldier whose job was to surveil the border ..."). Nonetheless, some other back-formations that were coined long ago have never managed to become standard, even though no exact synonyms are at hand. Enthuse is a prime example. Though the word has been in use since before the Civil War, most current dictionaries include warnings that it still irritates many people. Ultimately, all we have to go by is our own taste. Does a word irritate us? Then we should try to find some other way to make our point. If we can't—well, then we've discovered what the word is for.