Simple examples:
* "He boastfully declared that he was the best chess player in the school."
* "She spoke boastfully about her expensive new car."
* "The company boastfully advertised its latest product as revolutionary."
Examples with context:
* "After winning the championship, the team captain boastfully announced their dominance over all competitors."
* "He boastfully described his adventures in the Amazon rainforest, embellishing the story with exaggerated details."
* "The politician boastfully promised to solve all the country's problems if elected."
Using "boastfully" with synonyms:
* "He bragged boastfully about his recent promotion."
* "She swaggered boastfully, her confidence radiating."
Note: "Boastfully" is often used to indicate that someone is bragging or showing off in a way that is considered arrogant or self-important. It can also be used to describe someone who is exaggerating their accomplishments or possessions.