The Greek adjective asaleutos (ἀσάλευτος) means "unmovable, unshakeable, that which cannot be shaken" — from the alpha-privative a- (not) and saleuō (to shake, agitate). It describes absolute stability and permanence that no force can disturb.
The word appears twice in the New Testament with profound theological significance. In Acts 27:41, it describes the firm rock to which Paul's wrecked ship runs aground — the immovable sandbar. In Hebrews 12:28, it is used of God's kingdom: "since we are receiving a kingdom that cannot be shaken (asaleuton), let us be thankful." The author has just invoked the scene at Sinai — the mountain that shook — and contrasted it with Mount Zion. Everything in the old age was shakeable; the kingdom inaugurated by Christ is asaleutos. All earthly kingdoms, economies, and empires will be shaken (Hebrews 12:26–27); only what is of God remains immovable.