Chance money order (6)
I believe the answer is:
random
'chance' is the definition.
(similar in meaning)
'money order' is the wordplay.
'money' becomes 'rand' (I've seen this before).
'order' becomes 'om' (Order of Merit).
'rand'+'om'='RANDOM'
(Other definitions for random that I've seen before include "without any plan" , "Without pattern" , "Lacking any definite plan, order or purpose" , "can be hit-and-miss" , "Lacking a pre-planned pattern" .)