What does the idiom blow one's own horn mean?

• A. To celebrate someone else
• B. To boast about one's achievements
• C. To listen to music loudly
• D. To compliment others

Answer: (B)

This idiom is about self-promotion; it means bragging about one’s own achievements. The image of blowing a horn suggests loudly announcing what you have done to draw attention to yourself, often in a way that comes off as boastful. So the best meaning is boasting about oneself and one's accomplishments. It isn’t about celebrating others, listening to music loudly, or complimenting others. For example: “Whenever she finishes a project, she can’t resist blowing her own horn about how great she is.”