tr.v. be·trayed, be·tray·ing, be·trays
a. To give aid or information to an enemy of; commit treason against: betray one's country.
b. To inform upon or deliver into the hands of an enemy in violation of a trust or allegiance: "City investigators betrayed him to his bosses as a whistle-blower" (Selwyn Raab).
2. To be false or disloyal to: betrayed a cause; betray one's spouse.
3. To divulge in a breach of confidence: betray a secret.
4. To make known unintentionally: Her hollow laugh betrayed her contempt for the idea.
5. To lead astray; deceive: "She felt somewhat like a woman who in a moment of passion is betrayed into an act of infidelity" (Kate Chopin).
[Middle English bitraien : bi-, be- + traien, to betray (from Old French trair, from Latin trādere, to hand over; see TRADITION).]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.