'Precocious' definitions:

Definition of 'precocious'

From: WordNet
adjective
Characterized by or characteristic of exceptionally early development or maturity (especially in mental aptitude); "a precocious child"; "a precocious achievement" [ant: retarded]
adjective
Appearing or developing early; "precocious flowers appear before the leaves as in some species of magnolias"

Definition of 'Precocious'

From: GCIDE
  • Precocious \Pre*co"cious\, a. [L. praecox, -ocis, and praecoquus, fr. praecoquere to cook or ripen beforehand; prae before + coquere to cook. See 3d Cook, and cf. Apricot.]
  • 1. Ripe or mature before the proper or natural time; early or prematurely ripe or developed; as, precocious trees. [R.] --Sir T. Browne. [1913 Webster]
  • 2. Developed more than is natural or usual at a given age; exceeding what is to be expected of one's years; too forward; -- used especially of mental forwardness; as, a precocious child; precocious talents. [1913 Webster]