Tall Order Meaning

(idiomatic) A big job; a difficult challenge.

Example: 1911, E. Phillips Oppenheim Havoc, ch. 6—The Night Train from Vienna:
  "Guess they'd find it a pretty tall order trying to interfere with an American citizen."
2009, Tyler Hamilton, "50,000 green jobs ‘a tall order’," Toronto Star, 25 Feb. (retrieved 27 Feb. 2009):
  Frank Macedo . . . said creating that many jobs in three years is "a tall order."