NB! It seems this console command is not compatible with CS2.
Command Profile

M_CUSTOMACCEL

CS:GO

This command is used to choose what level of custom mouse acceleration you have. It can be set to disabled, or from a couple of choices.

Syntax
m_customaccel [0 / 1 / 2 / 3]

Description

This command is used to choose what level of custom mouse acceleration you have. It can be set to disabled, or from a couple of choices.

Syntax And Arguments

m_customaccel [0 / 1 / 2 / 3]
0 / 1 / 2 / 3 Enter a 0 after the command to turn custom acceleration off (default). Enter a 1 after the command to turn on custom max acceleration, meaning your camera will move faster the quicker you move your mouse. Enter a 2 after this command to turn on custom mouse acceleration, but for your X and Y axis sensitivity to be set by the m_pitch and m_yaw commands respectively. Enter a 3 after the command to turn on custom mouse acceleration, but for the mouse acceleration to be affected by your sensitivity .