Commander leading attack when everyone's out (7,6)
I believe the answer is:
general strike
'when everyone's out' is the definition.
(I've seen this before)
'commander leading attack' is the wordplay.
'commander' becomes 'general' (I have seen 'Military commander' mean 'general' so perhaps 'commander' could also mean 'general').
'leading' says to put letters next to each other.
'attack' becomes 'strike' (striking is a kind of attacking).
'general'+'strike'='GENERAL STRIKE'
(Other definitions for general strike that I've seen before include "all-out effort" , "National work stoppage" , "When everyone's out" , "national crisis" , "1926 withdrawal of labour" .)