In academic writing, certain near-synonymous adjectives are commonly found, among which are critical and important. This study aims to analyze the unique and shared patterns of these two near-synonyms in academic discourse and general use. In the British Academic Written English (BAWE) Corpus, both adjectives modify nouns such as point, method, and data. However, each has its individual uses: only critical modifies lure, path, and period, and only important modifies element, thing, and implication. However, the collocation patterns are somewhat different in a reference corpus. In the British National Corpus (BNC), critical modifies scrutiny and evaluation, while important modifies implication and consequence. The two adjectives behave differently in the two registers. By comparing the unique uses of a word in a specialized corpus, one can explore its regular patterns. Such patterns could be contrasted more clearly by comparing to a reference corpus. We argue that the collocation analysis from a reference corpus may need to be accompanied by a specialized corpus for the understanding of the vocabulary of a specialized field.