pibling-in-law Share definition Flag 1. The spouse of one's parent's sibling. 2. The sibling of one's parent-in-law. My pibling-in-law is a good person. pibling-in-law by Elivaldeq November 24, 2019 0 0 Get merch Get the pibling-in-law mug. Buy Now — $32.95 See more merch