MetTheoSyc 351:a.16 :ܟܕ ܫܝ̈ܦܢ ܪ̈ܚܘܬܐ ܒܚ̈ܕܕ‍[‍ܐ‏ : when millstones grind against one another
See the entire entry for šwp vb. to smear; grind down