Frank beginning to feel anger is in order for troops (4,4)
I believe the answer is:
open fire
'in order for troops' is the definition.
I can't tell whether this defines the answer.
'frank beginning to feel anger' is the wordplay.
'frank' becomes 'open' (synonyms).
'beginning to' says to take the initial letters.
'anger' becomes 'ire' (ire is intense rage).
The initial letter of 'feel' is 'f'.
'open'+'f'+'ire'='OPEN-FIRE'
'is' is the link.
Can you help me to learn more?
(Other definitions for open fire that I've seen before include "Perhaps start sniping" , "domestic hot spot" , "old-fashioned heater" , "Order for military" , "Initiate hostilities" .)