• bright, clever, tranquil, stable, reliable, erudite, intellectual, intelligent, percipient, hyperintelligent, learned, astute, level-headed, crafty, calm, fast, certain, quick, serious, sound, discerning, trained, shrewd, cunning, reasonable, acute, brainy, resourceful, prudent, well-read, informed, logical, careful, ultrasmart, educated, quick-witted, sharp, responsible, rational, thinking, wily, savvy, cerebral, steady, skilled, sane, sagacious, keen, predictable, apt, scholarly, perceptive, highbrow, unvarying, schooled, sensible, knowledgeable, sure, Sharp-witted, ingenious, wise, constant, unchanging, foxy, literate, well-advised, supersmart, smart, brilliant, judicious, sage, insightful, unchangeable, sapient, knowing, perspicacious, nimble, valid.