Suppressors do not fully silence guns.
A gun with a suppressor will be louder than an unsuppressed gun, but it will be much quieter than the sound of a gun without a suppressor. Gun suppressors are designed to muffle the sound of a gunshot and redirect the gasses that escape from the barrel of the gun. This process helps to reduce the amount of noise that is created when a gun is fired.
However, it is important to note that suppressors are not 100% effective at reducing noise levels. They are typically only able to reduce noise levels by about 30-35%. So even with a suppressor, there will still be some level of noise that is created when a gun is fired.