Thoroughly trendy dog found in Oz (2,4)
I believe the answer is:
in toto
'thoroughly' is the definition.
Both the answer and definition are adverbs. Perhaps there's a link between them I don't understand?
'trendy dog found in oz' is the wordplay.
I cannot quite see how this works, but
'trendy' could be 'in' ('in' can mean fashionable) and 'in' is found in the answer.
'dog' could be 'toto' (I've seen this before) and 'toto' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for in toto that I've seen before include "Completely - entirely (Latin)" , "overall" , "Tranquillity" , "As a whole (Latin)" , "Wholly" .)