'Blow great trumpet / horn' refers to:

Explanation

The phrase 'Blow great trumpet / horn' is idiomatic and means to boast. It involves talking about one's own achievements with the intention to impress others. The correct answer is 'Boast' because it aligns with this meaning. The other options do not fit the idiomatic expression: 'Violent flow of word' suggests aggressive speech rather than boasting; 'Celebrate enthusiastically' implies joy and group activity, not personal boasting; 'Eruption' signifies a sudden release, unrelated to the context of boasting.