Oxford英英辞典より

Sin

1.an offence against God or against a religious or mortal law
用例　to commit a sin
Confess your sins to God and he will forgive you

2.the act of breaking a religious or moral law
用例 a life of sin

3.(informal)an action that people strongly disapprove of
用例 It's a sin to waste taxpayer's money like that

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sinfle

morally wrong or evil
用例 sinful thoughts
It is singul to lie.