What does "loudmouth" mean?

One who talks too much or too loudly, especially in a boastful or self-important manner.

What is a synonym for "loudmouth"?

Common synonyms include: bellower, bigmouths, billyoh, blabbermouth, blabbermouths, blowhard.

Pronounced //ˈlaʊdˌmaʊθ//.

/ˈlaʊdˌmaʊθ/ noun, slang

noun, slang ·Moderate ·College level

Noun

1
One who talks too much or too loudly, especially in a boastful or self-important manner. derogatory, slang
"I hear every word spoken by the loudmouth in the next office."
2
a person who causes trouble by speaking indiscreetly wordnet

"The mayor is a know-it-all and a loudmouth."

From loud + mouth.