Expenditure absent one put into decorations (9)
I believe the answer is:
outgoings
'expenditure' is the definition.
(I've seen this before)
'absent one put into decorations' is the wordplay.
'absent' becomes 'out' (similar in meaning).
'one' becomes 'i' (Roman numeral).
'put into' is an insertion indicator.
'decorations' becomes 'gongs' (I can't justify this - if you can you should give a lot more credence to this answer).
'i' going within 'gongs' is 'goings'.
'out'+'goings'='OUTGOINGS'
Can you help me to learn more?
(Other definitions for outgoings that I've seen before include "Expenses" , "expeditions" , "Regular expenditure" .)