Genius
Person Of Exceptional Talent, Exceptionally Talented Person
noun
A person with genius and talent is a genius, or a person of exceptional talent. So smart!
俊才 is an advanced word usually only seen in writing. It tends to refer more to the kind of genius or talent that can be developed through effort. In that sense it differs from 天才, which is for the kind of genius that comes from heaven — either you have it or you don't.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
この問題集は俊才児を対象にして作られているので、あなたのお子さんには難しすぎますよ。
This textbook is designed for genius children, so it will be difficult for your kid.