mouth

1 mouth /ˈmaʊθ/ noun
plural mouths /ˈmaʊðz/
1 mouth
/ˈmaʊθ/
noun
plural mouths /ˈmaʊðz/
Britannica Dictionary definition of MOUTH
1 
: the opening through which food passes into the body : the part of the face that includes the lips and the opening behind them
[count]
[noncount]
2 
[count] : an opening in something — usually + of — see also goal mouth
3 
[count] : the place where a river enters the ocean
4 
[singular] informal : an unpleasant or offensive way of talking
— see also big mouth, loudmouth, smart-mouth

all mouth (and no trousers/action)

British, informal
— used to describe someone who talks a lot about doing something but never actually does it

born with a silver spoon in your mouth

— see born

butter wouldn't melt in someone's mouth

— see 1butter

by word of mouth

— see 1word

down in the mouth

: unhappy or depressed

foam at the mouth

— see 2foam

from the horse's mouth

— see 1horse

froth at the mouth

— see 2froth

hand to mouth

— see 1hand

heart in your mouth

— see heart

keep your mouth shut

1 
: to not say anything
2 
: to not talk about something (such as a secret)

look a gift horse in the mouth

— see 1horse

melt in your mouth

— see 1melt

mouth to feed

: a person (such as a child) who needs to be fed

put words in/into someone's mouth

— see 1word

put your foot in your mouth

— see 1foot

put your money where your mouth is

— see money

run your mouth

— see 1run

shoot your mouth off

— see 1shoot

shut your mouth

— see 1shut

take the words right out of someone's mouth

— see 1word
2 mouth /ˈmaʊð/ verb
mouths; mouthed; mouthing
2 mouth
/ˈmaʊð/
verb
mouths; mouthed; mouthing
Britannica Dictionary definition of MOUTH
[+ object]
1 
: to say or repeat (something) without really meaning it or understanding it
2 
: to form (words) with your lips without speaking

mouth off

[phrasal verb] informal
: to talk in a loud, unpleasant, or rude way