to boast; to brag; to talk big; to blow one's own horn
他总是喜欢吹牛皮，说自己多么厉害，但实际上却没做成什么大事。
He always likes to boast about how capable he is, but in reality, he hasn't accomplished anything significant.
Next Idiom
to boast; to brag; to talk big; to blow one's own horn