adj. sound·er, sound·est 1. Free from defect, decay, or damage; in good condition: Is the bridge sound? 2. Free from disease or injury. See Synonyms at healthy. 3. a. Marked by or showing common sense and good judgment; levelheaded: a sound approach to the problem. b. Based on valid reasoning; having no logical flaws: a sound conclusion; sound reasoning. See Synonyms at valid. c. Logic Of or relating to an argument in which all the premises are true and the conclusion follows from the premises. 4. a. Secure or stable: a partnership that started on a sound footing. b. Financially secure or safe: a sound economy. 5. Thorough; complete: gave their rivals a sound thrashing. 6. Deep and unbroken; undisturbed: a sound sleep. 7. Compatible with an accepted point of view; orthodox: sound doctrine. adv. Thoroughly; deeply: sound asleep. [Middle English, from Old English gesund.] soundly adv. soundness n. |
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