Sign on order two ways (4)
I believe the answer is:
omen
'sign' is the definition.
(omen is a kind of sign)
'on order two ways' is the wordplay.
'two ways' can mean two substitutions for 'way'.
'on' means one lot of letters go next to another.
'order' becomes 'om' (order of merit).
'way' becomes 'e' (Compass direction - East).
'way' becomes 'n' (Compass direction - North).
'om' next to 'e' is 'ome'.
'ome'+'n'='OMEN'
(Other definitions for omen that I've seen before include "Sign of a future event, good or bad" , "Prophetic significance" , "Harbinger, prophetic sign" , "Harbinger, portent" , "Sign of things to come" .)