What is "Chatter"

[Johnny Beeblebrox]

I was watching a DE razor review and "chatter" was very briefly mentioned in the context of the specific blade being used. Nothing came up when I looked on the TSR search function.
Can anybody point me in the direction of an explanation?
Ta in advance.

 

[TobyC]

Usually in razors with little blade support combined with a course beard and a steep shaving angle, the blade will flex and then spring back when cutting the hairs. A good razor and shallow angle will prevent it from happening.