Animal trained to work without worrying (8)
I believe the answer is:
sheepdog
'animal trained to work without worrying' is the definition.
I can't judge whether this defines the answer.
'animal trained to work' is the wordplay.
'animal' becomes 'sheep' (I have seen 'Woolly animal ' mean 'sheep' so perhaps 'animal' could also mean 'sheep').
'trained to work' becomes 'dog' (I can't justify this - if you can you should believe this answer much more).
'sheep'+'dog'='SHEEPDOG'
Can you help me to learn more?
(Other definitions for sheepdog that I've seen before include "could it be Old English?" , "Pastoral assistant?" , "eg Border collie" , "One drives over fields" , "Canine trained to control flock" .)