The Greek noun aposkiasma means a shadow cast, a variation caused by a shadow, or a shifting shadow. It comes from apo- and skia (shadow). The word appears only once in the New Testament in James's profound statement about God's unchanging nature.
Aposkiasma is found in James 1:17: 'Every good and perfect gift is from above, coming down from the Father of the heavenly lights, who does not change like shifting shadows [tropes aposkiasma].' This is one of the most beautiful descriptions of divine immutability in Scripture. Unlike the shadow a sundial casts (which shifts and changes throughout the day), God casts no 'turning shadow' — His character, goodness, and faithfulness never vary. This theological truth is the bedrock of trust: the same God who was good yesterday is good today. The immutability of God is the ground of all confident prayer and petition.