Merriam-Webster's Collegiate® Dictionary, 11th Edition
CRAZY
I. adjective (crazier; -est)
Date: 1566
1. full of cracks or flaws ; unsound , crooked , askew ,
2. mad , insane , b. impractical , erratic , being out of the ordinary ; unusual ,
3. distracted with desire or excitement , absurdly fond ; infatuated , passionately preoccupied ; obsessed , crazily adverb craziness noun
II. noun (plural crazies)
Date: 1867
one who is or acts crazy,
III. adverb
Date: 1887
extremely , wildly