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 replacements for 'way'.
'on' says to put letters next to each other.
'order' becomes 'om' (Order of Merit).
'way' becomes 'e' (Compass direction - East).
'way' becomes 'n' (Compass direction - North).
'om'+'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" .)