Keep moderator but remove moderator

How do you keep the moderator but remove them from the description?

You mean like... an undercover moderator?

ACP Advanced // Users & Groups // Group Administration // Create new group // Name it Undercover Moderator // Do all the settings you want // Make the group status hidden and uncheck colour group members // Write whoever you want to be an Undercover Mod in the Group Moderator Area // Save

if you mean on forums, go to admin panel>display>structure and hieracy>show forum moderators>no>save.