Good luck to somebody
Definition 1 of 1
Pro Tip 1/3Positive Reinforcement
Expressing support or encouragement for someone about to face a challenge. 
She's running her first marathon this weekend. Good luck to her!
Pro Tip 2/3Neutrality
Used when you're not involved in the outcome of the event you're referencing. 
Tom's buying a lottery ticket. Good luck to him!
Pro Tip 3/3Success Wishing
Good luck to somebody is often said right before the event. 
My sister has her final exam today. Good luck to her!