Yes it is possible, but in an indirect way. Here is one method: 

(I have to use screen shots to explain). Here is an example of `myModule` whose body prints a message to the screen, but the body is hidden

![enter image description here][1]

This is done by making the implementation `foo` in this case, be in a separate cell, then utilizing cell->cell properties feature to close the cell from view so it becomes hidden. The following two steps needs to be done:

![enter image description here][2]

The important point, is to have the implementation in a different cell to be able to close it. You can't close part of a cell. On a cell on its own. This can be easily extended for modules that take arguments as well.


 [1]: https://i.sstatic.net/PkdOt.png
 [2]: https://i.sstatic.net/VKyO0.png