Seen a melon exhibiting a hard outer coating? (6)
I believe the answer is:
enamel
'a hard outer coating?' is the definition.
'enamel' can be an answer for 'coating?' (enamel is a kind of coating). I am unsure of the 'a hard outer' bit.
'seen a melon exhibiting' is the wordplay.
'exhibiting' indicates a hidden word (I've seen 'exhibits' mean this).
'ENAMEL' is hidden in the letters of 'seen a melon'.
Can you help me to learn more?
(Other definitions for enamel that I've seen before include "hard cover" , "Hard gloss paint" , "Hard type of paint" , "Hard shiny coating on surface" , "Ale men (anag.)" .)