Custom pick list - delimiter?

You should be able to type in the value click enter, type in another value, click enter... it should be pretty quick.  There is no way to import picklist values at the moment.  What data are you storing in this picklist?  There is one work around to import data in, but that would involve making a reference to object field and storing the options as some object within Clarizen (risks, requests, cases, issues, etc.).

I too have a very long list and the below response is a bit of a joke.

That comment was 6 years ago. You can now use the Data Loader to import pick list entries, handy for long lists.