WordNet sense 1 (involving or causing danger or risk; liable to hurt or harm):

dangerous, unsafe

WordNet sense 2 (desperately determined):

do-or-die

WordNet sense 3 (firm in purpose or belief; characterized by firmness and determination):

resolute

WordNet sense 4 (arising from or marked by despair or loss of hope):

despairing

WordNet sense 5 (without hope because there seems to be no possibility of comfort or success):

hopeless

WordNet sense 6 (requiring attention or action):

imperative

WordNet sense 7 (fraught with extreme danger; nearly hopeless):

dire

WordNet sense 8 (being in or verging on a state of crisis or emergency):

critical

WordNet sense 9 (showing extreme courage; especially of actions courageously undertaken in desperation as a last resort):

heroic

WordNet sense 10 (possessing or displaying courage; able to face and deal with danger or fear without flinching):

brave, courageous