Top class dressing for painful condition derived from this creature (6)
I believe the answer is:
agouti
'this creature' is the definition.
(agouti is a kind of animal)
'top class dressing for painful condition' is the wordplay.
I cannot quite see how this works, but
'condition' could be 'gout' (gout is a kind of condition) and 'gout' is found in the answer.
'top' could be 'ai' (resembles A1, term for excellent) and 'ai' is present in the leftover letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'derived from' is the link.
Can you help me to learn more?
(Other definitions for agouti that I've seen before include "Long-legged rabbit-sized rodent on Central and South America" , "Burrowing rodent - IOU tag (anag)" , "Caribbean rodent" , "Guinea pig-like rodent" , "S.Amer. rodent" .)