Time of great danger (6)
I believe the answer is:
crisis
'time of great danger' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for crisis that I've seen before include "Turning point in disease" , "Decisive time, turning point" , "Crucial or decisive moment" , "Climax or turning point as in fever" , "Desperate situation" .)