Is there a way to check if character is moving backwards?

Well you can check if hes pressing the S key or the DownArrow. But im not sure if you mean like hes looking East but going torwards West.

this has to be in a localscript ofc

game:GetService("UserInputService").InputBegan:connect(function(input)
	if input.KeyCode == Enum.KeyCode.S then
	       print("went backwards")
	end
end)