Lifeless spies touring Australia to the north (5)
I believe the answer is:
azoic
'lifeless' is the definition.
(I've seen this before)
'spies touring australia to the north' is the wordplay.
'spies' becomes 'cia' (Central Intelligence Agency).
'touring' is an insertion indicator (touring can mean going round).
'australia' becomes 'oz' (informal name for Australia).
'to the north' says the letters should be written in reverse (in a down clue, letters go up or 'northward').
'cia' enclosing 'oz' is 'cioza'.
'cioza' backwards is 'AZOIC'.
(Other definitions for azoic that I've seen before include "lifeless" , "Showing no trace of life" .)