Deceive or betray one, as in If my memory does not play false, I met them years ago in Italy. [Late 1500s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
How to use play false in a sentence
Duke Robert was threatening; "he shall know what it is to play false with the heir of William the Norman!"God Wills It! | William Stearns Davis
Turning swiftly, he snarled and bit, at them in angry disbelief that his good little legs should play false with his stout heart.Greyfriars Bobby | Eleanor Atkinson
All of a sudden a rumour was spread abroad that the woman was about to play false, and to peach the rest.Lavengro | George Borrow
The dealer can play false cards; while the adversaries cannot afford to deceive each other.Bridge; its Principles and Rules of Play | J.B. Elwell
My ears are strung to-day, And play false airs invented by the wind.