So what's the difference between "good" and "well"?

"Good" is an adjective. This means it describes people, things and places, not verbs.

"She is a good student."

These sentences are correct:

These sentences are incorrect:

Sam behaves good.
They eat good.
She sings really good.
Well
"Well" is usually an adverb, and it generally describes actions.

"She dances well."
These sentences are correct:
- Sam behaves well.
- They eat well.
- She sings really well.
These sentences are incorrect:
- Sam is a well boy.
- They live in a well house.
- This is not a well place to live in.
  Note: "Well" can be used as an adjective. In such cases, it is usually not used before the noun, and it means "healthy" or "in a good state."
  
  For example:
  You don't look well.
  All is well with my family.
  Get well!

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