exocentric

(ĕkˌsō-sĕnˈtrĭk)

1. Of or relating to a group of syntactically related words, none of which is functionally equivalent to the function of the whole group. For example, none of the words in the phrase on the table is an adverb, yet they combine to form a phrase having adverbial function.
2. Of or relating to a compound word whose referent is not the same as the referents of any of its constituent parts. For example, the noun razorback does not refer to a type of back, but to a type of hog (one having a sharply ridged back).