Synonyms: fat, plump, overweight, obese
Antonyms: slim, thin
fat: having too much flesh or weighing too much
Example: You’ll have to eat less – you’re getting too fat.
plump: slightly fat in an attractive way
Example: the baby’s plump little arms She’s grown plumper now she’s stopped
overweight: having a body that weighs too much
Example: The doctor says I’m a little overweight.
obese: so fat that it is dangerous for health reasons
Example: Many children are becoming obese because of their unhealthy diets.
thin: not fat
slim: with a body that is thin in an attractive way