There is no difference as Lin is both clever and smart. If you wanted to be pedantic then I am sure there is a difference. However, if you asked a thousand people in the United Kingdom then probably 90% would say those words meant more or less the same. I would say clever and smart meant the same thing and I have spoken English for let me see 46 years now!!! I have never learned another language but I imagine you would want to make it as sinple as possible and not to over complicate. At the end of the day language is a tool to communicate with other people. If you used either the word clever or smart 100% of the people in the United Kingdom or dare I say the USA would know what you meant.