From Elizabeth I conceal set of moral values (5)
I believe the answer is:
ethic
'set of moral values' is the definition.
(I've seen this in another clue)
'from elizabeth i conceal' is the wordplay.
'from' indicates the answer is hidden within the clue.
'ETHIC' is hidden in the letters of 'elizabeth i conceal'.
(Other definitions for ethic that I've seen before include "Set of moral values" , "Moral value" , "Moral rule" , "Code of principles" , "System of principles" .)