actually, Stephen J. Gould, arguably one of the most accessible evolutionary biologists of the day, had a rationale for coining the word exaptation. you could look it up, but it boils down to this: he wanted a term that would include pre-adaptation and another concept which has been called "spandrels".

Gould has written a paper suggesting that the word “spandrel” be used in biology to name features that arise without initial adaptive functions (e.g., those that are architectural by-products of development) but take on new functions later in evolution (Gould 1997).

Gould had earlier proposed, in a paper with Elizabeth Vrba (Gould and Vrba 1982), that we call traits that perform a current adaptive function but arose either for some other function or with no adaptive function at all [my emphasis] as “exaptations.” Thus both preadaptations and “spandrels” qualify as exaptations. The terminology may seem very nitpicky, but it forces us to think about the details of a trait and how it might have evolved, and it forces us to go beyond the mere creation of plausible stories in the study of adaptation.

http://biosci264.bsd.uchicago.edu/adaptation.html