Verb

(head)

(undermine)

Verb

(undermin)

To dig underneath (something), to make a passage or for destructive or military purposes; to sap.

* 2009 , (Diarmaid MacCulloch), A History of Christianity , Penguin 2010, p. 312:

Martin, for instance, had on one occasion undermined a tree sacred to old gods, then stood in the path of its fall, but forced it to fall elsewhere by making the sign of the Cross.

(figuratively) To weaken or work against; to hinder, sabotage.

* {{quote-news, year=2012, date=April 19, author=Josh Halliday, work=the Guardian

, title= Free speech haven or lawless cesspool – can the internet be civilised? , passage=The growing use of social media to spread anger and dissent in the Arab world has been hailed by western governments as one of the chief justifications for a completely unfettered internet. The US is reportedly funding the secret rollout of technology in Iran in an effort to undermine internet censors in the country.}}

Verb

(en verb)

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. e.g. Quresh betrayed Sunil to marry Nuzhat

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.

To violate the confidence of, by disclosing a secret, or that which one is bound in honor not to make known.

To disclose or discover, as something which prudence would conceal; to reveal unintentionally; to bewray.

* {{quote-news

, year=2012 , date=May 24 , author=Nathan Rabin , title=Film: Reviews: Men In Black 3 , work=The Onion AV Club citation , page= , passage=Jones’ sad eyes betray a pervasive pain his purposefully spare dialogue only hints at, while the perfectly cast Brolin conveys hints of playfulness and warmth while staying true to the craggy stoicism at the character’s core. }}

* 1966 , Marc Léopold Benjamin Bloch, French rural history :

Again, to take a less extreme example, there is no denying that although the dialects of northern France retained their fundamentally Romance character, they betray many Germanic influences in phonetics and vocabulary, [...]

To mislead; to expose to inconvenience not foreseen to lead into error or sin.

To lead astray, as a maiden; to seduce (as under promise of marriage) and then abandon.

To show or to indicate; -- said of what is not obvious at first, or would otherwise be concealed.