Boast Boasting
Overconfidence; perhaps a hidden uncertainty about yourself or an attempt to feel superior to another person.
If someone else boasting: This depends on how you respond to this in the dream. It might reflect your own activities, or perhaps showing you what the dreamt of person is really like. See Characters of People in Dreams
Useful Questions and Hints:
If it is me boasting, why do I need to do that in the dream?
If someone else boasting, what do I feel about that – is this to do with feeling a lack in myself?
What is the subject of the boast and what connection do I have with that?
To find out more see Talking As and Being the Person or Thing