I am reading a book, called Minimalist Syntax: Exploring the Structure of English. At the beginning of chapter 2, when discussing the inflectional morphology of English verbs, the author says:
The most regular verb suffix in English is -ing, which can be attached to the base form of almost any verb (though a handful of defective verbs like beware are exceptions).
But a quick search on online language tools, such as Wiktionary, The Free Dictionary and Google NGrams reveals the existence of bewaring. Wiktionary even lists some book quotations. So, what is the author trying to say? In what respect beware is defective?
Best Answer
The Oxford English Dictionary writes that there are forms in which beware is inflected. For example, they write that the secondary sense is:
However, the primary sense of the verb is without these inflections. In the associated OALD, they only include the non-inflected type, and say that beware is only used in infinitives. It is this sense that most people use--without adding tense endings.
The author seems to be using only this sense of the verb, and referring to it as the sense of beware. He is not wrong in that this is the sense that most people will recognize. However, this does not mean that there have never been inflections added--they just didn't catch on into popular use. Now, the secondary use listed by the OED is not likely to be found anywhere except in old quotations. Beware is "defective" because it is a verb which doesn't take inflected endings (at least, not any more), so it has turned itself into a fairly irregular verb.