Is cheating a sin?

Basically, yes cheating can be classed as a sin.

• Biblical definitions

If you are looking at this from a religious angle then The Bible states that there are two types of lying - 'bearing false witness' and 'teaching false doctrines'.

• Deception

If you are asking is it a sin to cheat in, say, an exam or test you are knowingly deceiving another person, for example, the examiner or teacher, therefore bearing false witness. It would be like saying if you didn't get caught or nobody else found out it would be morally sound - this is not true as you are willingly deceiving someone else.

• Adultery

If you mean 'cheating' in the sense of having an amorous relationship with someone other than your partner then this could also considered as lying in The Bible - the Seventh Commandment states, "Thou shall not commit adultery" (Exodus 20:14). Although in the strictest biblical sense adultery is an act of sexual intercourse between a couple, one or both of whom are already married, present day understanding of adultery defines it as any sexual act with someone other than one's partner. I suppose it is all about the definition of the word adultery.

If you are having a relationship with someone who isn't your partner and you're worried about what the Bible says I guess that you're not a very good Christian anyway. If you looking for some kind of religious angle to alleviate your guilty conscience deep down you probably know you are in the wrong.