This article explores one of the earliest signs of metaphorical thinking in the Arabic-Islamic tradition under the semi-technical term ittisāʿ ‘extension’ or saʿat al-kalām ‘free parlance’ in early grammar works, with a focus on Sībawayhi’s Kitāb. Making the poetic šawāhid my point of departure, I find a strong correlation at the prima facie level between utterances that Sībawayhi characterizes using the phraseology of saʿat al-kalām and the type of imaginary metaphors that one encounters in badīʿ poetry (the ‘new style’). This correlation can only be explained if we consider the literary environment of 8th-century Iraq, where Sībawayhi was active. After analyzing several ‘metaphorical’ structures in Old Arabic, I further make the case that Sībawayhi’s observations regarding seemingly metaphorical language often blur the distinction between syntax and the lexicon. This study contributes to our understanding of early Arabic-Islamic theorizing of metaphorical language outside the term majāz, and outside the Qurʾānic-hermeneutical context.