"What is a man?"
अनुवाद:आदमी क्या है?
If I asked "What is a dog?" you might reply with "A dog is an animal. It walks on four legs and barks". The sentence "What is a man?" works in the same way, you could reply "A man is a grown up male human".
You could also use this sentence rhetorically - for example imagine a speech by a politician: "So I ask "what is a man?", is he someone who cheats, steals and rapes? No. A man is someone who is kind, passionate and caring. A man respects woman, a man respects every other living person..."