Frenzied offer by an artist (5)
I believe the answer is:
rabid
'frenzied' is the definition.
(I've seen this before)
'offer by an artist' is the wordplay.
'offer' becomes 'bid' (bid is a kind of offer).
'by' means one lot of letters go next to another.
'an artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'bid' after 'ra' is 'RABID'.
(Other definitions for rabid that I've seen before include "Extreme, fanatical" , "Raging (having been bitten by a dog?)" , "Ill from a mad dog bite?" , "Affected by 24 across" , "Fanatical like mad dog" .)