a riddle or puzzle — a verbal puzzle posed for amusement that you try to solve
子どもたちは休み時間になぞなぞで盛り上がっていた。
The children were having fun with riddles during break time.
雑誌に面白いなぞなぞが載っていたので挑戦してみた。
There was an interesting riddle in the magazine, so I tried it.
このなぞなぞの答えは一度気づくと簡単だ。
Once you notice the trick, the answer to this riddle is easy.