Everyone else's definition of Goink is either racist or just total total garbage. Goink is the sound you make when you walk up and take something from someone in a fun and or jovial way. Example. Someone is eating their happy meal, you walk up behind them, reach for a fry and as you take said fry you say "Goink". Past tense = Gank.
I walked up to Lisa slowly, and then Goink, I stole her pen and ran off.