動詞 betray:

1. reveal unintentionally
   同義詞：bewray
2. deliver to an enemy by treachery
   同義詞：sell
3. disappoint, prove undependable to; abandon, forsake
   同義詞：fail
4. be sexually unfaithful to one's partner in marriage
   同義詞：cheat on, cheat, cuckold, wander
5. give away information about somebody
   同義詞：denounce, tell on, give away, rat, grass, shit, shop, snitch, stag
6. cause someone to believe an untruth
   同義詞：deceive, lead astray

1. As long as you don't betray me, I'll do whatever you ask me to (do).
   只要你不出賣我，要我做什么我都愿意。
2. His accent betrayed the fact that he was foreign.
   他的口音顯露出他是外國人。
3. The smoke from cooking betrayed the presence of the enemy.
   炊煙暴露了敵人的存在。
4. He betrayed his country.
   他背叛了他的國家。

be.tray

v.tr.（及物動詞）
be.trayed,be.tray.ing,be.trays

To give aid or information to an enemy of; commit treason against:
背叛，出賣：給敵方提供幫助或情報(bào)；通敵叛國：
例句：
betray one`s country.
背叛祖國

To deliver into the hands of an enemy in violation of a trust or allegiance:
出賣：違背信任或忠誠地送給敵方：
例句：
betrayed Christ to the Romans.
將耶穌出賣給羅馬人

To be false or disloyal to:
背信或不忠實(shí)：
例句：
betrayed their cause; betray one`s better nature.
不忠實(shí)他們的事業(yè)；背離善良本性

To divulge in a breach of confidence:
以違背信任而泄露：
例句：
betray a secret.
泄露秘密

To make known unintentionally:
無意識地暴露：
例句：
Her hollow laugh betrayed her contempt for the idea.
她的大笑顯示了她對此觀點(diǎn)的蔑視

To reveal against one`s desire or will.See Synonyms at reveal
泄露愿望，泄露欲望：泄露某人的愿望或欲望參見 reveal
To lead astray; deceive.See Synonyms at deceive
引入歧途；欺騙參見 deceive

來源：
Middle English bitrayen
中古英語 bitrayen
bi- [be-]
bi- [前綴，表.全面地，徹底地.]
trayen [to betray] from Old French trair from Latin tr3dere [to hand over] * see tradition
trayen [背叛] 源自 古法語 trair 源自 拉丁語 tr3dere [交付] *參見 tradition

【引伸】
betray.al
n.（名詞）
betray.er
n.（名詞）