So, let's do a quick review. If you are doing something defiantly, you are being bold, impudent, or rebellious. If you are planning to definitely do something, then you are certain you will be doing it. Here are a few examples to set the record straight:
- She pouted defiantly when her mother grounded her.
- "Don't you dare do that," said her father. In response, she defiantly broke the plate by dashing it to the floor.
- I definitely want to see Peter Jackson produce The Hobbit.
- I definitely hate it when students use defiantly when they mean definitely.