headquarter The verb headquarter occurs in both transitive and intransitive senses: The magazine has headquartered the reporters in a building that houses many foreign journalists. The European correspondent will headquarter in Paris. But this verb usage does not sit well with many people, and in an earlier survey a majority of the Usage Panel found both these examples unacceptable in formal writing. Although there is a lot of evidence for these usages, you would do best to use alternative expressions, for example: The magazine has just assigned him to (or has stationed him in) a building that houses many foreign journalists. The European correspondent will make her headquarters in Paris (or will make Paris her headquarters).    healthy / healthful Some people like to maintain a distinction between healthy and healthful. Healthy, they say, should be used to mean “possessing good health,” and only healthful should mean “conducive to good health.” People who hold this view are swimming against the tide of history, for healthy has been used to mean “healthful” since the 16th century. You can find the “healthful” use of healthy in the works of many distinguished writers, with this example from John Locke being typical: “Gardening … and working in wood, are fit and healthy recreations for a man of study or business.” Therefore, both healthy and healthful are correct in these contexts: a healthy climate, a healthful climate; a healthful diet, a healthy diet. historic / historical Historic and historical have different usages though their senses overlap. Historic refers to what is important in history: the historic first voyage to the Moon. It is also used of what is famous or interesting because of its association with persons or events in history: a historic house. Historical refers to whatever existed in the past, whether regarded as important or not: a minor historical character. Historical also refers to anything concerned with history or the study of the past: a historical novel, historical discoveries. While these distinctions are useful, don’t be surprised if you see these words used interchangeably, as in historic times or historical times   if or whether In informal writing, both if and whether are standard for introducing a clause indicating uncertainty after a verb such as ask, doubt, know, learn, or see: We shall soon learn whether (or if) it is true. In such contexts, however, the use of if can sometimes create ambiguities. Depending on the intended meaning, the sentence Let her know if she is invited might be better paraphrased as Let her know whether she is invited or If she is invited, let her know.   important Some people object to the use of the phrase more importantly in place of more important as a means of introducing an assertion, as in More importantly, there is no one ready to step into the vacuum left by the retiring senator. But both forms are widely used, and there is no obvious reason for preferring one or the other    impracticable / impractical The adjective impracticable applies to a course of action that is impossible to carry out or put into practice: Refloating the sunken ship proved to be impracticable because of its fragility. Impractical can also be used in this way, but it can also be weaker in sense, suggesting that the course of action would yield an insufficient return or would have little practical value. A plan for a new baseball stadium might be rejected as impracticable if the site was too marshy to permit safe construction, but if the objection were merely that the site was too remote for patrons to attend games easily, the plan would better be described as impractical.    in behalf of / on behalf of A traditional rule holds that in behalf of and on behalf of have distinct meanings. Accordingly, you should use in behalf of to mean “for the benefit of,” as in We raised money in behalf of the earthquake victims. And you should use on behalf of to mean “as the agent of, on the part of,” as in The guardian signed the contract on behalf of the child. But as the two meanings are quite close, the phrases are often used interchangeably, even by reputable writers. incredible / incredulous Incredible means “hard to believe, unbelievable”: His explanation of the cause of the accident was simply incredible. It is often used more loosely to mean “astonishing,” as in The new pitcher has an incredible fastball. Incredulous usually means “skeptical, disbelieving,” as in The incredulous reporters laughed at the manager’s explanation of how the funds disappeared. It is sometimes extended to mean “showing disbelief,” as in an incredulous stare. You may occasionally see incredulous used where you would expect incredible, as in an incredulous display of rudeness. This usage is not well established, however, and is widely considered an error.    individual You normally use the noun individual to refer to an individual person as opposed to a larger social group or as distinguished from others by some special quality: “This is not only a crisis of individuals, but also of a society” (Raymond Williams). She is a real individual. Since the 19th century, however, there have been numerous objections to use of the word to refer simply to “person” where no larger contrast is implied, as in Two individuals were placed under arrest or The Mayor will make time for any individual who wants to talk to her. This use of individual is common in official statements, as the examples imply, and lends a formal tone that you may find inappropriate for many contexts. Remember that the words person and people can do the same job perfectly well.    Infrastructure The term infrastructure has been around since 1927. It usually refers collectively to roads, bridges, rail lines, and similar public works that are required for an industrial economy, or a portion of it, to function. This often includes telecommunications facilities, such as telephone lines and microwave towers. The term has had specific application to the permanent military installations necessary for the defense of a country. Perhaps because of the word’s technical sound, people now use infrastructure to refer to any substructure or underlying system. Big corporations have their own financial infrastructure of smaller businesses, for example, and political organizations have their infrastructure of groups, committees, and admirers. This political sense may have originated during the Vietnam War in use by military intelligence officers, whose task it was to delineate the structure of the enemy’s shadowy organizations. Today we hear that conservatism has an infrastructure of think tanks and research foundations and that terrorist organizations have an infrastructure of people who are sympathetic to their cause. This extended use referring to people does not sit well with the Usage Panel, however. Seventy percent found it unacceptable in the sentence FBI agents fanned out to monitor a small infrastructure of persons involved with established terrorist organizations 