This paper presents an investigation into imperfect rhyme patterns in Korean rap, with a focus on the role of feature similarity in the formation of rhyming pairs. The study analyzes 8,990 rhyming pairs and 2,594 imperfect rhyming pairs extracted from 90 Korean rap songs. To measure feature similarity and its impact on rhymability, the study employs Similarity values and Observed-Expected values, focusing on three feature classes: place, manner, and major class. The findings of this study indicate that, with few exceptions, feature similarity plays a fundamental role in the formation of imperfect rhymes, which is in line with previous research by Kawahara (2007) and Ha (2001). This study contributes to our understanding of the role of feature similarity in rhymability, and sheds light on the underlying mechanisms that govern the formation of rhyming pairs. (Kyungpook National University · Yeungjin University)