Abstract This paper examines the modification of nominal compounds by attributive adjectives in English. It draws on a distinction between compound-external (i.e. syntactic) and compound-internal (i.e. morphological) modification. An analysis is presented of more than 1000 pertinent cases, which are roughly equally divided into two-, three- and four-noun compounds. Irrespective of their positions, all constituents of all compound sizes are found to be susceptible to modification. Modification is subject to two major parameters—functional role and depth of embedding. Major heads are much more accessible than minor heads which in turn are more accessible than modifiers. The greater the structural depth of a constituent, the lower the probability of it being modified. This pattern of results suggests that the adjective in compound-internal modification has access to the structure of the full compound. That is, morphological modification has a curious syntactic ring to it. This unexpected behaviour of the adjective blurs the distinction between syntactic and morphological modification and argues against the strict separation of syntax and morphology.