What is this fake player cutout thing called? It appears to be mesh. It looks like it's used simply as a visual point-of-reference for certain drills.
You can see it being used in this video.
This is a mannequin for skill training.
Is it used in football/soccer training to increase precision penalty (so is called (slave) defensive template barrier)
In american football and basketball is often easy to find it called as man defensive mannequin.
I do not know if it exists a "real" name for it, but those are probably the easy denomination you can find for it