A dimit is a choice that you can make to revert your stats to 'noobliness', or back to what they were when you were originally thawed. By doing this, all of your items (except for those that are reset safe) will be sent to your Display Case, which will be locked until the completion of the dimit.
You complete a dimit by reaching the last possible degree attainable 'when' you dimit. While you're in a dimit, any item received from another player or bought from the auction will be sent directly to your Display Case.
There are a few perks to dimiting, not all of it is bad. First of all, you receive a +1 boost to whatever your Yang is when you dimit. If your Yang is Evil when you dimit, during and after that dimit you will receive one more evil than you would have. (Or, if the case may be, one less good, since good and evil are on the same axis.)
You will also receive a boost to a stat of your choice, out of five choices. It's up to you to find out what each of these dimit paths 'do', but it's fairly straightforward in it's explanation from even the 'name' of the path.
If you complete more than one dimit, you will receive a power boost to your Yang 'each' time you dimit, and it will stack. The boost to the chosen stat (the dimit path) will also stack, but not in the same way. If you choose one path the first time you dimit and then chose a different path the next time, there will be NO boost to the first chosen path. Instead, you will have a boost to your second chosen path, doubled. You cannot have a boost to more than one path. Remember that when you choose.
Once you complete a dimit (get to the highest degree attainable) your display case will be unlocked, and you will be sent a report on how fast you finished it. You can now dimit again, or go on to bigger and better things, if you choose.