step-great-grandnibling Share definition Flag 1- Sibling's step-great-grandchild. 2- Stepsibling's great-grandchild. My step-great-grandnibling is a good person. step-great-grandnibling by User655 July 25, 2021 0 0 Get merch Get the step-great-grandnibling mug. Buy Now — $32.95 See more merch