adj

• (informal) Very unexpected; wildly surprising.
  "The game had a crazy ending."
• (obsolete) Flawed or damaged; unsound, liable to break apart; ramshackle.
  "Buchanan shewed her into a room adjoining to Mr. Steele's dressing-room, and separated from it by a very crazy partition."
• (obsolete) Sickly, frail; diseased.
  "Over moist and crazy brains."

adv

• (slang) Very, extremely.
  "That trick was crazy good."

noun

• (slang, countable) An insane or eccentric person; a crackpot.
  "Now drink up, you knuckleheads! Have a blast! It's our night, you crazies! Chloe, where are you?"
• (slang, uncountable) Eccentric behaviour; lunacy; craziness.
  "Then again, her whole evening was full of crazy, and she didn't know what else to do."