Aides not spoiling state of calm (8)
I believe the answer is:
sedation
'state of calm' is the definition.
'sedation' can be an answer for 'state' (sedation is a kind of state). I'm not certain of the 'of calm' bit.
'aides not spoiling' is the wordplay.
'spoiling' indicates anagramming the letters.
'aides'+'not'='aidesnot'
'aidesnot' anagrammed gives 'SEDATION'.
Can you help me to learn more?
(Other definitions for sedation that I've seen before include "Effect of calming drug" , "State of drug-induced calm" , "The administering of sleep-inducing drugs" , "Calming with drugs" .)