clearheaded

adj

1. astute, discerning, perceptive, penetrating, piercing; perspicacious, percipient, discriminating, appercipient; bright, smart, sharp, shrewd, keen, quick, Inf. quick on the trigger; sagacious, sapient, wise.

2. alert, wide-awake, aware, Inf. heads-up, Inf. on the ball, Inf. on the stick, Inf. on one's toes, Sl. nobody's fool; observant, on the watch, on the alert, on the lookout; heedful, mindful, careful, cautious, wary, chary; attentive, vigilant, watchful, Argus-eyed, on the qui vive; eagle-eyed, hawk-eyed, lynx-eyed, sharp-eyed.

3. lucid, rational, sane, reasonable, sound, clear-thinking, clear-sighted, level-headed; judicious, prudent, wise, sober, circumspect; thoughtful, sensible, intelligent, reasonable; comprehending, thinking, knowing, cognitive; long-sighted, far-sighted, far-seeing, long-headed; resourceful, creative, imaginative.

4. composed, collected, calm, steady; untroubled, undisturbed, unperturbed, unshaken, unruffled, unex-cited; poised, self-possessed, self-restrained, cool-headed, tranquil, serene, placid.