Extraordinary rendition (sic) a foolish act (12)
I believe the answer is:
indiscretion
'a foolish act' is the definition.
'indiscretion' can be an answer for 'act' (indiscretion is a kind of act). I'm not certain of the 'a foolish' bit.
'extraordinary rendition sic' is the wordplay.
'extraordinary' is an anagram indicator.
'rendition'+'sic'='renditionsic'
'renditionsic' anagrammed gives 'INDISCRETION'.
Can you help me to learn more?
(Other definitions for indiscretion that I've seen before include "Careless Whisper" , "Tactless deed" , "Faux pas" , "Tactless remark or action" , "Imprudence" .)