If you're thinking of "diction" as the choice and use of words:
* Jargon: This refers to specialized vocabulary used by a particular group or profession, often making communication unclear to outsiders.
* Slang: This refers to informal language used in casual conversation, often considered inappropriate in formal settings.
* Mumbling: This refers to speaking indistinctly or unclearly, making it difficult to understand what someone is saying.
* Rambling: This refers to speaking in a disorganized or incoherent manner, lacking structure and clarity.
If you're thinking of "diction" as clarity and articulation:
* Vagueness: This refers to unclear or ambiguous communication, lacking specific details.
* Ambiguity: This refers to a situation where something can be interpreted in multiple ways, making it difficult to understand the intended meaning.
* Indistinctness: This refers to a lack of clarity or sharpness in speech, making it difficult to discern words or sounds.
Ultimately, the best antonym for "diction" depends on the specific context you're using it in. Consider the intended meaning and choose the word that best captures the opposite idea.