Guy: DIKY - Stands for "Do I Know You". Often the day after a guy and girl hooks up and the girl texts him he will write back DIKY? to show that he is no longer interested in texting about stupid shit with her. If she replies asking what it means this definition is responded back, and no further response from the guy will happen.
Girl: Your an asshole
Girl: are you serious
Girl: so your not even gonna respond