Fanatical attempt by Royal Academy to make a purchase? (5)
I believe the answer is:
rabid
'fanatical' is the definition.
(I know that fanatical can be written as rabid)
'attempt by royal academy to make a purchase?' is the wordplay.
I cannot really understand how this works, but
'attempt' could be 'bid' (bid is a kind of attempt) and 'bid' is located in the answer.
'royal' could be 'r' (abbreviation) and 'r' is present in the answer.
'academy' could be 'a' (abbreviation for academy) and 'a' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for rabid that I've seen before include "Burning" , "Fanatical like mad dog" , "Extremely fanatical" , "Fanatical, infected" , "Fanatical - hydrophobic" .)