fat

1 fat /ˈfæt/ adjective
fatter; fattest
1 fat
/ˈfæt/
adjective
fatter; fattest
Britannica Dictionary definition of FAT
1 
: having a lot of extra flesh on your body : having a lot of body fat
◊ Fat can be an insulting word when it is used to describe a person.
— opposite 1thin
2 
: having a full, rounded form
◊ A fat lip is a lip that is swollen because of injury, especially from being punched.
3 
: unusually wide or thick
4 
informal : containing, providing, or costing a large amount of money
5 
informal + disapproving : successful or wealthy
6 
baseball : easy to hit

big fat

— used for emphasis

fat chance

— see 1chance

it ain't over until/till the fat lady sings

— see lady
2 fat /ˈfæt/ noun
plural fats
2 fat
/ˈfæt/
noun
plural fats
Britannica Dictionary definition of FAT
1 
[noncount] : the soft flesh on the bodies of people and animals that helps keep the body warm and is used to store energy
— see also baby fat
2 
: an oily solid or liquid substance in food
[noncount]
[count]
— see also deep fat
3 
[noncount] : an amount that is more than what is usual or needed : excess

chew the fat

— see 1chew

live off/on the fat of the land

◊ To live off/on the fat of the land is to live very well, enjoying the best things that are available without having to work hard to get those things.