Race off, released, nonchalant (8)
I believe the answer is:
carefree
'nonchalant' is the definition.
(thesaurus)
'race off released' is the wordplay.
'off' is an anagram indicator.
'released' becomes 'free' ('free' can be similar in meaning to 'released').
'race' anagrammed gives 'care'.
'care'+'free'='CAREFREE'
(Other definitions for carefree that I've seen before include "without worrying?" , "Take a chair" , "Without anxiety or responsibilities" , "relaxed" , "Not bothered" .)