Top definition
1. If you have a fat mouth, you talk too much, especially about things that should be secret.

2. Someone that's very talkative, especially when boastful.

3. One that informs, especially against another/others.

4. Someone who talks too loud and boastful; whoride.
That chick's a fat mouth! Don't tell her anything!
by Mr. Terrence L. Trezvant April 07, 2007
Mug icon

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the shirt
2
Used to describe someone who cannot shut up, talks with verbal diahorrea or who swears a lot- almost used in that case interchangeably with 'foulmouth'.
She's such an anonying little fatmouth.

Shut up you fatmouth little bitch!
by whitecracker556 March 08, 2009
Mug icon

Dirty Sanchez Plush

It does not matter how you do it. It's a Fecal Mustache.

Buy the plush
3
1. the kind of person that talks crap and may have pathetic comebacks

2. someone who spreads rumors, even if they aren't true

3. that one person you can't tell your secrets to
Boy: You're a freak and you're ugly.

Girl: Kid, you need to back off and leave me the hell alone before I freaking punch you in your big, fat mouth.
by BatmansGotSwag October 18, 2011
Mug icon

Golden Shower Plush

He's warmer than you think.

Buy the plush
4
someone who runs their mouth and talks all the time.
you wouldnt want to tell them anything, because they are likely to tell the world.

watch your back around a fat mouth.
People named RJ tend to be a liar and a fat mouth.
by Jaeeeeeeeeeeeeyy October 10, 2010
Mug icon

Dirty Sanchez Plush

It does not matter how you do it. It's a Fecal Mustache.

Buy the plush
5
"oops i dropped my wallet"
*enter fatmouth*
by Gritto October 09, 2003
Mug icon

Donkey Punch Plush

10" high plush doll.

Buy the plush