“Fragging” an enemy in a shooter game means to kill it, to blow it into pieces.
But there is also defragging, an activity mostly conducted in offices: employees are not actually working but just pretending to do so.
The term refers to “defragmenting the file system”, a maintenance function built into Microsoft Windows. Originally it was serving the purpose of optimizing how the content of files is laid-out on the harddisk by moving parts of the same file close together so the read/write head of the harddisk wouldn’t have to move so much. If management personal would drop by and see the defragmentaion running, they wouldn’t notice that no work is being done as managers of course lack any technical knowledge and the classic defrag visualization in Windows 95 and 98 looked really complicated and active (see animation above).
In later versions of Windows the visualization changed to boring and useless lines. But history demands that you should use the verb defragging all the time you are pretending to work, no matter what tactic you apply.