A gonnie is a person who is mentally challenged, they struggle to do many simple tasks. It can be hard to spot a gonnie as their exterior is normal, however, delve a little deeper and participate in a conversation with them and their true gonnieness is quickly revealed. Common signs of being a gonnie range from general slowness, being inept at hand eye coordination activities, poor spelling and grammar and an often vacant expression.
'Hey, you see Abbie only scored a 3 letter word on countdown?' 'I know, she's such a gonnie'.