Next Day Depression. Typically used to define the feeling that one has the morning after a long night of drinking and perhaps some ill timed decisions. For males, that means fucking that fat chick. For chicks, that means being a slut and kissing 5 of your boyfriend's friends. Usually accompanied by a overwhelming sense of apathy and refusal to step out of your room for fear of someone seeing you who knows what you did the previous night.
"Where's Jim at?"
"Oh he stayed in...bad case of NDD."
"Dear teacher: I did not get your paper done on timebecuase instead of doing it on Sunday like I should have, I sat under the covers of my bed dealing with a serious case of NDD."
It is used on DarkNet markets, mostly in reviews. It means that the ordered item was/(will be) delivered to buyer the next day after ordering (mostly rare).
Vendor (product details): Shipping times EU: 1-3 business days, mostly NDD
Customer (product rating): 5/5. Extremely fast - NDD! Good stealth