Wikipedia
Tahrif
(, "distortion, alteration") is an Arabic term used by Muslims for the alterations which Islamic tradition claims Jews and Christians have made to the revealed books, specifically those that make up the Tawrat (or Torah), Zabur (possibly Psalms) and Injil (or Gospel).
Traditional Muslim scholars, based on Qur'anic and other traditions, maintain that Jews and Christians have changed the word of God.