This thesis contributes to a problem that traditionally has been seen as belonging to psychology as a discipline: the study of personality words - words such as shy, outgoing, selfish, creative, etc. Their meanings and the semantic system that they form have been a research area for psychology for over a century, both theoretically and methodologically. In this thesis I apply a different perspective, in which I bring the study of these words into the domain of linguistics - in particular, lexical semantics. To indicate this important disciplinary shift, I have named this study "The Linguistics of Personality". I position this research within both linguistics as a discipline and personality research as a research field. Maintaining this perspective, the thesis is structured to engage in a dialogue with personality studies while maintaining a clear linguistic methodology and disciplinary stance. In particular, I critically examine the tradition most closely associated with the study of personality words in psychology - the psycholexical approach, which has produced one of the most commonly used personality models, the "Big Five". Through a literature review, I demonstrate that the Big Five primarily reflects a linguistic phenomenon rooted in the English lexical semantic system. In each of the four analytical chapters I address one of the Big Five personality factors (Extraversion, Agreeableness, Neuroticism, and Openness to Experience). I analyse the lexical semantics of selected personality words commonly used as "measures" of each factor in English and in Russian, thereby providing a cross-linguistic perspective. The lexical semantic analysis is performed using the Natural Semantic Metalanguage (NSM) approach. NSM is an approach that explicates the meaning of a word through a unified language of semantic primes. This approach enables the analysis of language units using language itself, thereby avoiding the need to introduce extra-linguistic concepts when analysing linguistic data. By relying on corresponding primes in both English and Russian, the analysis provides a basis for cross-linguistic comparison while avoiding ethnocentric biases inherent to each language. The underlying principle is to deconstruct meaning, express it in a unified metalanguage, and conduct comparisons. I employ a corpus-assisted approach, extracting quantitative data and individual examples from one of the largest comparable corpora available in English and Russian - the TenTen corpus family. These corpora are web-based and are managed using Sketch Engine, an advanced tool used in lexicographic and semantic research. Using the NSM approach, representative words for different personality factors are analysed. Chapter 3 examines words related to the Extraversion factor, namely shy and outgoing in English, supplemented by a cross-linguistic comparison with the Russian term zastenčivyj ("shy"). In Chapter 4 attention turns to the English word selfish and its corresponding Russian equivalent ègoist(ka), representative of the Agreeableness factor. Chapter 5 delves into the Neuroticism factor, focusing on the analysis of moody in English and kapriznjy in Russian. Finally, Chapter 6 analyses the English term creative in comparison to its Russian counterparts to explore the Openness to Experience factor. While highlighting potential issues with the use of personality words in psychological assessment, this thesis also aims to propose solutions. Experimental questionnaire items formulated in simple, cross-translatable words are suggested as a new approach to personality assessment, complementing the analysis of selected personality words in each chapter. Chapter 7 discusses the practical applications of the analysis and proposes further cross-disciplinary steps. The concluding Chapter 8 overviews the significance of the study's results for linguistics and advocates the integration of lexical semantics into broader research problems, emphasising the importance of developing the linguistics of personality for better understanding word meanings across disciplines.