Grandpa Yahr Share definition Flag An old individual who is running low on viagra and is in need of any type of sexual activity. The most often is anal sex. Wow. That guy looks like he could be a grandpa yahr.Did a grandpa yahr call you last night? Grandpa Yahr by protector of youth June 26, 2009 0 0 Get merch Get the Grandpa Yahr mug. Buy Now — $32.95 See more merch