emmdam:
Can a born-again christian refer watching wrestling show as a form of entertainment or a sin?

Moyadex:
It's simple.
Whenever you're confused, becareful who you listen to.

If you don't know if something is wrong, then see Jesus doing it. If you see Jesus doing it, what would be your reaction?

For example,

Can you picture Jesus engaging in wrestling?
Is it befitting?

If it's not appropriate, then wrestling is inappropriate.

Then ask yourself if entertaining yourself with inappropriate things is good for you as a Christian? Or picture Jesus watching what's inappropriate! What do you think?

Hiswordxray:

That is a wrong question.
The right questions are
what good is watching wrestling to me?
As a child of God will watched wrestling build me up, will it help me to grow up?
Does watching wrestling have any negative effect on my spiritual life?
Does watching people in violent act teach me to turn my face when someone slap me?
Does watching aggressive people teach me to be humble?
Can I find another form of entertainment that will impact my spiritual life positively?
Can I get to a place where doing the things of God is both pleasurable and entertaining to me?

Kobojunkie:
Sin has absolutely nothing to do with any of what you described above. It isn't arbitrarily defined.

Instead, Sin is disobedience of God's direct commandment to us obedience is instead what God calls us to. God is a God of Laws and Jesus Christ is God's New Agreement/Law in the Kingdom of God. What this means is that God's Truth and Law is contained in the very teachings and commandments given to us by Jesus Christ, and in this Law there are approximately 100 laws which define clearly for us what is sin.

So, to answer the OP'S question, you would have to access the teachings and commandments of Jesus Christ in order to find what, if any, law is impacted in this.

Also, note, that it is against God's Law aka sin to add, change, or remove laws as you please from God's Law so those of you who go around, for instance, declaring sin that which God never indicated as such, do so against God - you sin when you do that.

emmdam:
Can a born-again christian refer watching wrestling show as a form of entertainment or a sin?

Moyadex:
1. Sin is going against God's will. And I haven't declare anything sinful here. Open the pages of your Bible, it's said that whatever you conscious declared as sin is sin for you indeed.

2. I'm basically asking him to look at Jesus, and see what Jesus would want. Isn't that the main purpose of Christian life?