—adj. 1. not true or correct; erroneous: a false statement. 2. uttering or declaring what is untrue: a false witness. 3. not faithful or loyal; treacherous: a false friend. 4. tending to deceive or mislead; deceptive: a false impression. 5. not genuine; counterfeit.
6. based on mistaken, erroneous, or inconsistent impressions, ideas, or facts: false pride. 7. used as a substitute or supplement, esp. temporarily: false supports for a bridge. 8. Biol.having a superficial resemblance to something that properly bears the name: the false acacia. 9. not properly, accurately, or honestly made, done, or adjusted: a false balance. 10. inaccurate in pitch, as a musical note.
—adv. 1. dishonestly; faithlessly; treacherously: Did he speak false against me? 2. play someone false, to betray someone; be treacherous or faithless.