Apart from the choice of word, I want to add that the entire construction of the sentence is old-fashioned and very unnatural. We’d say things like: He seems smart. Maybe he knows the answer. Let’s ask him. He thinks he’s very intelligent, but I haven’t seen evidence of it. If he thinks of himself as clever, he’s clearly mistaken.

James's examples are good, but in our parts, a difference is that "clever" generally has a good connotation.

I would choose clever. Here are some sentences that use these words: Smart - He is doing well in school. He is pretty smart Intelligent - He has a collage diploma and is able to some challenging problems in creative ways. He is really intelligent. Wise - He is an old man. He went trough a lot of stuff throughout his life and learned a lot of things. He is a wise man. Clever - This guy can really be a nuisance. He always finds clever ways to bend the rules and get away with stuff. He's really clever. Explanation of each word: You would use smart when someone for example solved a math problem correctly. Intelligent is a little bit more than smart. You can tell from someone's behavior or speech that they're an intelligent person. Wise is mostly used for older people who have a lot of experience from their long life. They are wise. They can give you advise that smart or intelligent people can't. And lastly clever is similar to smart, but it is mostly used when someone is smart and creative in kind of a bad way. A hacker finds clever ways to break into a computer. A clever CEO found a loophole in the law to pay less taxes. A student found a clever way to cheat in the test without getting caught. Hope this helps =D