Something that is bespoke is something that is unique and specially made purely for the purpose it serves. It is not copied from anywhere nor is it used for any other purpose other than the one it was specifically made for.
Just like a bespoke painting is made just for the person who comissioned it our bespoke web designs are unique and will never be used again for another site.
Your website is exactly that, yours and yours alone.
See also Custom Design