Definition Visibility

Definition Visibility Who can see your Character's Definition
The Definition Visibility controls whether users can inspect the Character Definition.
Chippy's Definition Visibility
If a Character has Private Character Visibility, the Definition Visibility is automatically set to Private as well.
However, if Definition Visibility is set to Private, users will not be able see the text of the Definition.

Deciding on Public vs Private

Many people will simply leave this Public, to allow others to inspect and learn from how their character was made. However, you may want to set this to Private if you don't want to reveal some secret technique, or if there is information in the definition that might spoil an experience or game if it can be inspected.
This setting only hides the longer Definition field. All other characteristics of your Character (name, greeting, short/long description, categories) will be visible if they can chat with the Character at all (Character Visibility is Unlisted or Public).