In terms of communication:
* Silence: The complete absence of a message.
* Misunderstanding: A failure to convey or receive the intended message.
* Noise: Anything that interferes with the transmission or reception of a message.
In terms of meaning:
* Meaninglessness: The lack of any clear or intended message.
* Inconsistency: A message that contradicts itself or other messages.
* Irrelevance: A message that has no bearing on the situation at hand.
In terms of purpose:
* Action: The opposite of a message would be a direct action instead of a communication.
* Inaction: The complete absence of any response to a message.
It's important to consider the specific context to determine the most appropriate opposite of "message."