Untreated leather artist we hid inside (7)
I believe the answer is:
rawhide
'untreated leather' is the definition.
'rawhide' can be an answer for 'leather' (thesaurus). I am unsure of the 'untreated' bit.
'artist we hid inside' is the wordplay.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'inside' means one lot of letters goes inside another.
'we' going around 'hid' is 'whide'.
'ra'+'whide'='RAWHIDE'
Can you help me to learn more?
(Other definitions for rawhide that I've seen before include "Stiff untanned leather" , "Untanned animal skin cut to make whips and ropes" , "Whip" , "Leather before tanning" .)