do–or–die

do–or–die /ˈduːwɚˈdaɪ/ adjective
do–or–die
/ˈduːwɚˈdaɪ/
adjective
Britannica Dictionary definition of DO–OR–DIE
1 
always used before a noun : very determined
2 
— used to describe a situation in which you have to do something or you will fail, lose, etc.