Impious act remarkably considerate! (11)
I believe the answer is:
desecration
'impious act' is the definition.
'desecration' can be an answer for 'act' (desecration is a kind of act). I'm unsure of the 'impious' bit.
'remarkably considerate' is the wordplay.
'remarkably' indicates anagramming the letters (I've seen this in other clues).
'considerate' with letters rearranged gives 'DESECRATION'.
Can you help me to learn more?
(Other definitions for desecration that I've seen before include "Damage of anything sacred" , "Violating" , "Violent disrepect" , "doing harm to something sacred" , "Violently disrespectful treatment" .)