the feeling that you have when you are in such a bad situation that you are willing to take risks in order to change it

There was a note of desperation in his voice. 他的声音里透出破釜沉舟的决心。

In desperation, they jumped out of the window to escape the fire. 情急之下，他们跳出窗户躲避大火。

an act of desperation 破釜沉舟之举

the feeling of needing or wanting something very much

his desperation to survive 他强烈的求生欲望