1) When you invite a person to do something that you pride yourself in and they are better
at it than you. You usually use this word if you are somewhat of a
sore loser.
2) The person who is better at something than your friend even though your new at it can also use this word to
be humble and comfort their friend. This definition can be used to show off sometimes.
1) Jeff: "Hey I'm pretty good at this!"
Paige: "
Pshhhh, it's just beginner's luck, bro."
2) Molly: "OH DUDE YOU ARE SO AWESOME AT THIS!"
David: "Nah, you're much better. I just have beginner's luck.
Its nothing!"