So-called noise is used to hide underlying payload packets length. Without it GoVPN provides confidentiality and authenticity of messages, but not their timestamps of appearance and sizes.
You may turn on -noise option, that forces to fill up all outgoing packets to their maximum (MTU) size. As it can be applied only to outgoing traffic, you should enable it on both sides in most cases.
Pay attention that this can dramatically increase your traffic! It is turned off by default.