Webster's Revised Unabridged Dictionary · 1913

Betray

Betray (be*trā") , transitive verb

[Old English betraien, bitraien; pref. be- + Old French trair to betray, French trahir, from Latin tradere. See Traitor.]

1.
To deliver into the hands of an enemy by treachery or fraud, in violation of trust; to give up treacherously or faithlessly; as, an officer betrayed the city.
Jesus said unto them, The Son of man shall be betrayed into the hands of men. — Matt. xvii. 22
2.
To prove faithless or treacherous to, as to a trust or one who trusts; to be false to; to deceive; as, to betray a person or a cause.
But when I rise, I shall find my legs betraying me. — Johnson
3.
To violate the confidence of, by disclosing a secret, or that which one is bound in honor not to make known.
Willing to serve or betray any government for hire. — Macaulay
4.
To disclose or discover, as something which prudence would conceal; to reveal unintentionally.
Be swift to hear, but cautious of your tongue, lest you betray your ignorance. — T. Watts
5.
To mislead; to expose to inconvenience not foreseen to lead into error or sin.
Genius... often betrays itself into great errors. — T. Watts
6.
To lead astray, as a maiden; to seduce (as under promise of marriage) and then abandon.
7.
To show or to indicate; -- said of what is not obvious at first, or would otherwise be concealed.
All the names in the country betray great antiquity. — Bryant