The term "lukewarm" has been used in literature with a remarkable versatility, functioning both as a literal description of moderate temperatures and as a metaphor for indifference or half-heartedness. In some works, such as à Kempis’ The Imitation of Christ ([1], [2], [3]), "lukewarm" criticizes a spiritual or emotional tepidness, suggesting a lack of passionate commitment. Conversely, other texts employ it in its literal sense: etiquette guides and cookery manuals detail precise requirements for water temperature in washing or culinary preparations ([4], [5], [6], [7]). Meanwhile, in political and social commentary, authors like Thomas Jefferson and Dostoyevsky juxtapose "lukewarm" attitudes against more extreme stances or ideologies ([8], [9], [10]). This dual usage underscores the term's evolution in literature, where it elegantly bridges the physical and the metaphorical to enrich both narrative texture and critical commentary.