In this study, we examine the advantages and disadvantages of the existing limited semantic opacity of idiomatic expressions. To complement this, we aim to differentiate semantic opacity within the relationship between the overall meaning and the meaning of constituent elements based on the principle of semantic agreement and attempt to conduct research that better aligns with linguistic reality through the analysis of linguistic data that incorporates this approach. To achieve this, we intend to propose a new perspective on the semantic opacity of restricted collocations corresponding to the most typical lexical function, Oper, of restricted collocations. Through experimental analysis, it was possible to observe that many restricted collocations have their primary meanings. Indeed, semantical non-transparency of restricted collocations can be categorized into three semantic aspects. First, abstract noun leads semantic opacity of restricted collocations. And whether there are direct or indirect sematic derivations from primary meaning can increase semantic opacity. Last, as metaphorical meaning addition or structural transition occurs, semantic opacity becomes even higher.