Tang Rhymes (Tangyun) and Collected Rhymes (Jiyun) record its pronunciation as ku (rising tone), which is the same as the pronunciation for the character meaning cave. Broadly Elegant (Boya) defines it as to strike. Yangzi's Regional Expressions (Fangyan) records that in the Southern Chu region, the act of pushing and struggling with one another is called this. Also, Collected Rhymes (Jiyun) records its pronunciation as hu (rising tone), which is the same as the pronunciation for the character meaning suddenly. The meaning is the same. Another interpretation is that it means to remove dust.