Consternation among the national armed forces (5)
I believe the answer is:
alarm
'consternation' is the definition.
(synonyms)
'among the national armed forces' is the wordplay.
'among' says the answer is hidden in the clue.
'ALARM' is hidden within 'national armed forces'.
(Other definitions for alarm that I've seen before include "Noise that wakes" , "Distress signal" , "Device sounding danger" , "Flap" , "Burglar deterrent" .)