This study examines the internal semantic structure of a set of near-synonym adjectives: important, essential, vital, necessary and crucial. I used the British National Corpus (BNC) and 9 traditional reference materials as source data. I applied a corpus-based behavioural profile approach. The study focuses its attention on their distributional patterns especially types of nouns that each adjective modifies. Some of the findings challenge the several existing descriptions of this set of near-synonym adjectives by the traditional reference materials. For example, the traditional reference materials cite many examples of vital as modifier of abstract nouns but the corpus data indicates that it is mostly modified by concrete and dual nouns. This study justifies the theory and applicability of the BP approach for studying the semantic and usage patterns of a set of synonyms
Keywords: British National Corpus (BNC), behavioural profile, distributional pattern, internal semantic structure, near-synonym
