Jade trumpet for a novice (9)

I believe the answer is:

greenhorn

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'for a novice' is the definition.
(greenhorn is a kind of novice)

'jade trumpet' is the wordplay.
'jade' becomes 'green' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'trumpet' becomes 'horn' (synonyms).
'green'+'horn'='GREENHORN'

Can you help me to learn more?

(Other definitions for greenhorn that I've seen before include "One learning" , "Tenderfoot" , "One's not experienced" , "An inexperienced person of emerald hue?" , "Person with no experience" .)

I've seen this clue in The Daily Express.

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