Key material drawn by Hergé conclusively? (5)
I believe the answer is:
ebony
'key material' is the definition.
(I've seen this in another clue)
'drawn by herge conclusively?' is the wordplay.
'drawn' becomes 'bony' (I can't explain this - if you can you should give a lot more credence to this answer).
'by' says to put letters next to each other.
'conclusively?' says to take the final letters (the letter that concludes the word).
The last letter of 'herge' is 'e'.
'bony' after 'e' is 'EBONY'.
Can you help me to learn more?
(Other definitions for ebony that I've seen before include "Very dark black" , "Very dark brown" , "Wood - Boyne (anag)" , "Hard block tropical wood" , "Tree with blackish wood" .)