poomyster Share definition Flag 1. a cute baby that poops a lot 2. refering to ones significant other 1.ah look at that cute little poomyster 2. I miss my poomyster I haven't seen him/her all day. poomyster by Dee December 28, 2004 0 0 Get merch Get the poomyster mug. Buy Now — $32.95 See more merch