Oxford Dictionary
level-headed
level-headed ▶adjective calm and sensible. DERIVATIVES level-headedly adverb, level-headedness noun
Oxford Thesaurus
level-headed
level-headed adjective sensible, practical, realistic, prudent, circumspect, pragmatic, wise, reasonable, rational, mature, commonsensical, full of common sense, judicious, sound, sober, businesslike, no-nonsense, sane, composed, calm, cool, collected, {cool, calm, and collected }, serene, relaxed, at ease, confident, well balanced, equable, moderate, unworried, unmoved, unemotional, cool-headed, hard-headed, balanced, self-possessed, unruffled, even-tempered, imperturbable, reliable, dependable, with one's feet on the ground; informal unflappable, together. ANTONYMS excitable.