Sweet is an adjective. It talks about something with a lot of sugar in it.
- A mug of sweet tea.
- She makes very sweet desserts.
Sweetie is a noun.
You can call someone a sweetie if you like them very much.
- Come here sweetie and give your auntie a hug.
- Good morning, sweetie! Did you sleep well?
- I’ve had many nice conversations with the man next door. He’s a real sweetie.
Sweets are sometimes called sweeties by young children or by adults speaking to young children.
- Sorry but the sweetie jar is empty.
- If you are a good boy, mummy will buy you some sweeties.
