Delexicalization is a central semantic tendency and a major characteristic pattern of behavior for high frequency words in corpora. It is an inevitable outcome of co-selection and shared-meaning in communication. Previous studies on delexicalization focused on the features of a few delexicalized verbs. This paper is a corpora-based study of delexicalization of adjectival modifiers in Chinese and English. It investigates, within the theoretical frameworks of progressive delexcalization and shared meaning, the semantic features of the Chinese adjectival modifiers, kexue, kexuede, feifa and feifade, as well as their corresponding items in English, scientific and illegal. Results indicate that these modifiers, in most cases, have lost their semantic content to varying degrees, and that they no longer modify head nouns as their word class label might suggest but take on special roles of intensifying the meanings of head nouns, serving to realize the speaker's attitudinal meanings. The paper argues that what delexicalization reveals is the intrinsic meaning relations within the collocational sequence and that delexicalization of an individual word tightly ties in with the lexicalization of the phraseological unit as a whole, bringing to the fore part of the rich complexities covered in the idiom principle.