What does Judges 14:12 mean?

Samson said to them, 'Let me give you a riddle. If you can solve it during the seven days of the party, I'll give each of you a set of clothes and a fancy robe. But if you can't, you owe me the same.' Judges 14:12 - Modern Text Bible

(Samson challenges his companions with a riddle, turning the party into a contest with high stakes.)