A pal upset about shaggy wool producer (6)
I believe the answer is:
alpaca
'wool producer' is the definition.
(I've seen this in another clue)
'a pal upset about' is the wordplay.
'upset' indicates anagramming the letters.
'about' becomes 'ca' (short for circa).
'pal' is an anagram of 'lpa'.
'a'+'lpa'+'ca'='ALPACA'
'shaggy' acts as a link.
This may not be right. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for alpaca that I've seen before include "Long-haired animal related to the llama" , "(Woollen cloth from) relative of llama" , "S American mammal related to the llama" , "South American mammal" , "Llama's relative" .)