Prolixity is a notion which, throughout the history of linguistic thought, is regularly opposed to that of brevity, and based on it is the precept of avoiding in a narrative length and details that are irrelevant in context. While this notion is hardly examined in detail nowadays and sometimes only related directly to ‘higher complexity’, in some texts of the 18th century it plays a central role in considerations of the comprehensibility of texts. This contribution shows to what extent it is defined during this period more broadly and sometimes more precisely than in modern ap-proaches. The special focus of this study is the analysis of prolixity in texts of J. Chr. Adelung, who examins causes, effects, contents and linguistic forms of prolixity and set prolixity in regard of comprehensibility, clarity, simplicity and complexity, by bringing out the relativity of these relationships.