Although issues such as the meaning of the word, history and classification of slang have been written extensively and especially studied by linguists; the issue of what it adds to the literary text has not been given much attention. The use of slang in fictional texts is based on some historical reasons, sociological determinations, and the author's desire for realism. However, it is necessary to look at the answer to the question of how the function of slang in the text provides an opportunity for the author in the use of language rather than the content of the literary text. Slang can be read as an objection to the language of the period. In this article, based on Jonathon Green's Slang A Very Short Introduction, the theoretical structure of slang is examined and classification and criteria are emphasized. Then, the historical development of slang in Turkish and slang dictionaries in Turkish are briefly mentioned. The function of slang in literary texts is discussed and Kemal Tahir's relationship with language is evaluated in this context. Finally, the novel Esir Şehrin Mahpusu is analyzed in terms of slang-language-meaning connections and it is tried to show how the novelist uses slang in an implicit function as an objection to the established order.