To spill beans not good, evil (3)
I believe the answer is:
sin
'evil' is the definition.
(synonyms)
'to spill beans not good' is the wordplay.
'to spill beans' becomes 'sing' (both can mean to reveal a secret).
'not' indicates named letters should be taken away.
'good' becomes 'g' (abbreviation).
'sing' with 'g' taken out is 'SIN'.
(Other definitions for sin that I've seen before include "It breaches the moral law" , "grave offence" , "Immoral action" , "Serious transgression" , "Breach of morality" .)