Merriam-Webster's Collegiate® Dictionary, 11th Edition
UTMOST
I. adjective see: out Date: before 12th century situated at the farthest or most distant point ; extreme , of the greatest or highest degree, quantity, number, or amount ,
II. noun Date: before 12th century the most possible ; the extreme limit ; the highest attainable point or degree , the highest, greatest, or best of one's abilities, powers, and resources