Yonker Share definition Flag Someone who masturbates a lot. Over 10 times a day. Usually a person who is stupid. Brandon is such a yonker, he plays with his penis all day in english and he mistakes cats for chickens. Yonker by Audessy March 16, 2009 0 0 Get merch Get the Yonker mug. Buy Now — $32.95 See more merch