braggadocious
adjective mainly US informal disapproving uk/bræɡ.əˈdəʊ.ʃəs/ us/bræɡ.əˈdoʊ.ʃəs/
傲慢的，自负的;自吹自擂的，夸夸其谈的
praising yourself or speaking too proudly about your own achievements or importance
"I could do that," she said, imitating his braggadocious tone. “我可以做到，”她模仿他自负的口气说道。