Elaborate treat with German is perfect (10)
I believe the answer is:
watertight
'perfect' is the definition.
Both the answer and definition are adjectives. Maybe you can see an association between them that I don't see?
'elaborate treat with german' is the wordplay.
'elaborate' indicates an anagram (I've seen this in other clues).
'german' becomes 'g' (abbreviation).
'treat'+'with'+'g'='treatwithg'
'treatwithg' with letters rearranged gives 'WATERTIGHT'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for watertight that I've seen before include "Proof against leaking" , "Closely sealed" , "Impregnable" , "Unassailable" , "seaworthy" .)