Meaning of 'She has some mouth on her'?

What’s the meaning of “she has some mouth on her”?

The idiom comes from an episode (S03E03) of Seinfeld:

-He loves that pen.
-Come on.
He talks about it all the time.
He goes on and on about how it writes upside down, how astronauts use it.
He never should have offered it.
-He didn't think you'd accept.
-Well, he was wrong.
I know his wife.
She has some mouth on her. She'll tell everyone in the condo now that you made him give you the pen. They're talking about it right now.

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has a [some] mouth in this context seems to imply:

big mouth a talkative person, especially one who lacks discretion. dict.com

and:

shoot your mouth off informal also shoot off at the mouth : to talk foolishly, carelessly, or too much about something

She tends to shoot her mouth off.
Try not to shoot your mouth off about this to anyone.

learnersdict.com

lastly a gossip:

: to talk about the personal lives of other people

They spent the afternoon gossiping on the phone.
They often gossip with each other about their neighbors.

— gossiper noun, plural gossipers [count]

a malicious gossiper.  [learnersdict.com][3]