Intelligent, a.
Etymology: [L. intelligens, intellegens, -entis, p. pr. of intelligere, intellegere, to perceive; inter between + legere to gather, collect, choose: cf. F. intelligent. See Legend.]
1. Endowed with the faculty of understanding or reason; as, man is an intelligent being.
2. Possessed of intelligence, education, or judgment; knowing; sensible; skilled; marked by intelligence; as, an intelligent young man; an intelligent architect; an intelligent answer.
3. Gognizant; aware; communicate. [Obs.] Intelligent of seasons. Milton. Which are to France the spies and speculations Intelligent of our state. Shak.
Syn. -- Sensible; understanding. See Sensible.
Shades of meaning
Fernald has no entry of its own for intelligent; he lists it under clever, sagacious.
Where he writes about it:
A knowing child has more knowledge than would be looked for at his years, perhaps more than is quite desirable, while to speak of a child as intelligent is altogether complimentary. — from astute