overconfident       
adjective (also over-confident) uk/ˌəʊ.vəˈkɒn.fɪ.dənt/ us/ˌoʊ.vɚˈkɑːn.fə.dənt/
 过于自信的,自负的
having or showing too much confidence
  He is overconfident and cocky. 他过于自信和自大。 
 I'm not overconfident or arrogant, but I do believe in my own ability. 我没有过分自信或傲慢,但我确实相信自己的能力。 
 - More examples
 - I think my expectations were high and I was maybe a little bit overconfident.
 - Swift progress made us overconfident.
 - Over-confident brashness may not impress an interview panel.