Novel
Original, Innovative, Inventive
noun, な adjective
Something that has sliced newness into the world is novel and original. Just imagine the world as a place of things that are already done. If you want to get something innovative and inventive in there, you have to slice that oldness open to make space for the new.
斬新 is often used when you want to commend someone's creativity, novelty, or forward-thinking. However, it can also be used as a polite way of saying something is unusual or unexpectedly different, without openly calling it strange.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
すごく斬新なアイディアなので、後者よりも最初の案の方がいいと思います。
I prefer the former idea to the latter because it is a much more original idea.