Hide module – open dialog: File > Project Structure Ctrl + Alt + Shift + S
Hide module: in opened Dialog select module which will hidden and click on minus (left upper corner)
If module is hidden, you can permanetly delete module from disk. But if you want using module in future, copy module into other folder (not into AndroidProjects folder and his subbfolders) and delete module permanetly from project and disc. Right mouse click on module and select from menu Delete.
If you want import the backup copy to project, use: File>New>Import mudule