Dry Behind The Ears Meaning

(idiomatic) Seasoned or experienced; mature, especially with respect to judgment.

Example: 1850, Springfield Rep., (Whig.), Daily (Columbus) Ohio Statesman, 9 May, p. 3, col. 4:
  Why, you irreclaimable donkey, don’t you know the “notice” was an advertisement? When will you get dry behind the ears?
1910, Jack London, Burning Daylight, ch. 3:
  When you fellers was his age, you wa'n't dry behind the ears yet. He never was no kid. He was born a full-grown man.
1914, Edgar Rice Burroughs, The Mucker, ch. 6:
  "You're past twenty-one," he said, "an' dry behind the ears."
2001, William Safire, "Essay: Advance The Story," New York Times, 22 Oct. (retrieved 5 Oct 2010):
  That wearing of blinders by our intelligence agents was recently revealed by The Washington Post's columnist and editor Jim Hoagland, who is dry behind the ears, to say the least.