משנה על דברים 22:1

Only that which is spun or woven is forbidden under the law of kilayim, as it says, “You shall not wear shatnez” (Deuteronomy 22:1, that which is shua (combed) tavui (spun) and nuz (woven). Rabbi Shimon ben Elazar says: [the word shaatnez means that] he [the transgressor] is perverted (naloz) and causes his father in heaven to avert himself [from him].