What does it mean to have a decided mouth?

The phrase "decided mouth" isn't a standard idiom or expression in English. It's likely a unique phrase used in a specific context, and its meaning would depend on that context.

Here are some possible interpretations based on its literal components:

* Decided: Meaning strong, firm, or resolute.

* Mouth: The opening in the face through which we speak, eat, and breathe.

So, "decided mouth" could potentially mean:

* A mouth that speaks with conviction and determination: This could describe someone who is outspoken, assertive, and doesn't shy away from expressing their opinions.

* A mouth that is set in a particular expression: This could describe someone with a strong jawline, a stern or resolute look, or a determined expression.

* A mouth that is used for strong, forceful speech: This could describe someone who shouts, argues, or speaks loudly and emphatically.

To understand the true meaning, you'll need to provide more context. Please tell me where you encountered this phrase, and I can help you understand its intended meaning.