Here are some synonyms for "defiantly":
* Rebelliously
* Boldly
* Resolutely
* Stubbornly
* Disobediently
* Contrarily
* In a challenging way
* With defiance
Example sentences:
* The child stared defiantly at his parents, refusing to apologize.
* The team fought defiantly against the odds, refusing to give up.
* She walked defiantly towards the crowd, ignoring their jeers.
Note: "Defiantly" is often used to describe a person's attitude or behavior, but it can also be used to describe the way something is done, such as "The building stood defiantly against the storm."