Which is another word for worst Communication?

It's difficult to give a single perfect synonym for "worst communication" because the nuance depends on the context. Here are some options, depending on what you want to emphasize:

General Negativity:

* Abysmal communication

* Dreadful communication

* Terrible communication

* Appalling communication

* Ineffective communication

* Breakdown in communication

* Communication failure

Specific Issues:

* Miscommunication (if the problem is misunderstanding)

* Lack of communication (if there's simply not enough information shared)

* Unclear communication (if the message is confusing)

* Conflicting communication (if different messages are given)

* Poorly-timed communication (if the message is delivered at an inappropriate time)

Consequences:

* Communication breakdown

* Communication disaster

* Communication catastrophe

The best word will depend on the specific situation and the effect you want to convey.