unoutgrown

From un- +‎ outgrown.

unoutgrown (not comparable)

1. Not having been outgrown.
   • 1851 November 14, Herman Melville, Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley, →OCLC, page 82:

     […] still, from the audacious, daring, and boundless adventure of their subsequent lives, strangely blend with these unoutgrown peculiarities, a thousand bold dashes of character, not unworthy a Scandinavian sea-king, or a poetical Pagan Roman.