P Sirach 34:30 :ܕܣܚܐ ܡܢ ܡܝܬܐ ܘܗܦܟ ܩܪܒ ܠܗ܂ ܡܢܐ ܐܗܢܝ ܡܢ ܡܣܚܘܬܗ‏ : one who washes due to a dead body and goes back near it, what benefit did he derive from his washing?
See the entire entry for masḥū, masḥūṯā n.f. washing