Delay disrupted trade in army allowance (11)
I believe the answer is:
retardation
'delay' is the definition.
(retardation is a kind of delay)
'disrupted trade in army allowance' is the wordplay.
'disrupted' is an anagram indicator.
'in' means one lot of letters goes inside another.
'army allowance' becomes 'ration' (I can't justify this - if you can you should believe this answer much more).
'trade' with letters rearranged gives 'etard'.
'etard' going into 'ration' is 'RETARDATION'.
Can you help me to learn more?
(Another definition for retardation that I've seen is " Slowing; lag".)