The phrase "hush mouth" refers to a person who is quiet or reserved. The opposite of this would be someone who is talkative or outspoken. Antonyms for "hush mouth" could include words like gregarious, outgoing, loquacious, voluble, or chatty. These terms describe individuals who are inclined to speak their minds, share their opinions, and engage in conversation freely. They are often characterized by their sociable and approachable nature, and may be found in settings like parties, group discussions, or public gatherings. Alternatively, some antonyms for "hush mouth" are vulgar, loudmouthed or obnoxious, referring to those who are excessively boisterous or crude in their speech.