The article attempts to determine the nature of meanings in the semantic space of the lexicon by revealing the content of metaphors. A three-level classification of metaphors is presented within the scope of the article. Its main criterion is the degree of difficulties in their comprehension. The metaphors are arranged according to the principles of fluent and crystalized intelligence. A semantic structure of a word is viewed as a multi-level configuration of meanings. It is fixed by a dominant invariant meaning. The analysis of the English substantive “a leg” is presented. We have developed a new approach to the phenomena under consideration called Res Militaris, vol.12, n°3, November issue 2022 2130 the invariant-component method. As a result, the obtained semantic metaphorical clusters have lead to the lexical invariant definition. The latter is viewed as a set of basic dominant components that form the semantic core of a polysemous word. The results of the study led to the conclusion that lexical invariants make it possible to successfully decode metaphors of the first basic level according to our classification.