1. To be left alone or ditched by your friends
2. If you're talking to someone and they ignore you
Claire: I know all his mates have just dingied him - laughed at!
2. Lauryn: I just said I didn't want to see him anymore, what do you think?
Lauryn: Are you even listening?
Carolyn: You what?
Lauryn: Oh my God, dingied a dillion!