high A1

/haɪ/ Reaching a great distance up from the ground; tall.

highest C2+

/ˈhaɪəst/ greatest in height, rank, degree, or value

higher C2+

/ˈhaɪɚ/ at or to a greater height, degree, or rank

highness C2+

/ˈhaɪnəs/ the state of being high; a title of honour for royalty