The Aramaic adjective qaddish is the Aramaic equivalent of Hebrew qadosh (H6918) and means holy, saint, or set apart. It appears in Daniel (4:8–9; 5:11; 7:18–27; 8:13) to describe both God's angelic messengers ('holy ones') and the people of God ('saints of the Most High'). The word preserves the core semantic of holiness: separation for God's purposes.
Daniel uses qaddish to describe both the holy watchers (angels, 4:13) and the saints who will receive the eternal kingdom (7:18, 22, 27). The same root behind Hebrew holiness (qadosh) is at work here — set apart from the common, dedicated to God. The promise in Daniel 7:27 that 'the sovereignty, power and greatness of all the kingdoms under heaven will be handed over to the holy people (qaddishin) of the Most High' anchors New Testament kingdom theology. God's holy people will ultimately reign with Christ.