Surprise attack in the morning north of outback (6)
I believe the answer is:
ambush
'surprise attack' is the definition.
(ambush is a kind of surprise attack)
'morning north of outback' is the wordplay.
'morning' becomes 'am' (as in 12:00 AM).
'north of' says to put letters next to each other (in a down clue, some letters go above others).
'outback' becomes 'bush' (I've seen this before).
'am'+'bush'='AMBUSH'
'in the' acts as a link.
(Other definitions for ambush that I've seen before include "Weakening" , "Launch attack from cover" , "Lie in wait; trap" , "Attack from concealed position" , "Attack from concealment" .)