The aim of this thesis is to compare the meanings of two adjectives (soft and mild) that are usually recognized as synonymous. The semantic relation of synonymy is essential for the whole thesis and it is, therefore, dealt on in both the theoretical and the practical part. Special attention is paid to the notion of cognitive synonymy. In the practical part (i.e., the actual analysis), I analyze the corpora data with the intention to determine whether soft and mild function as cognitive synonyms in certain contexts. The theoretical part follows modern linguistic theories and concepts with special emphasis put on two linguistic phenomena: the semantic relation of synonymy and collocations. Modern linguistics has been collecting data from large databases of written texts that are commonly known as text corpora. In this work, I work with two of them: British National Corpus (BNC) and Corpus of Contemporary American English (COCA). Special attention is paid to noun phrases in attributive position.