Neglect an order for the thing in question (4)
I believe the answer is:
omit
'neglect' is the definition.
(synonyms)
'an order for the thing in question' is the wordplay.
'an order' becomes 'om' (Order of Merit).
'for' is a charade indicator (letters next to each other).
'the thing in question' becomes 'it' (I can't explain this - if you can you should believe this answer much more).
'om'+'it'='OMIT'
Can you help me to learn more?
(Other definitions for omit that I've seen before include "Fail to include" , "Leave out or neglect" , "Leave out, perhaps in error" , "Leave something out" , "Neglect to include" .)