LIke most simliar but distinct verbs -- the difference is not in meaning, its in HOW THEY ARE USED i.e. the full meaning (full power) of the verb is made clearer when a verb is combined with a noun (a collocation) to defy the authorities The protesters defied the authorities and now they are in jail. to breach protocol When you're talking to the President, follow the rules and don't breach protocol (=the proper procedures) to breach the walls Genghis Khan was able to breach the walls of the city with a battering ram. to violate customs When is Rome, do as the Romans -- don't violate the customs of the local people. to violate privacy The NSA has violated the privacy of ... everyone in the world? brutally violate / a brutal violation The actions of the NSA are a brutal (=extreme, hard) violation of the 4th Amendment of the US Constitution. flagrantly violent The actions of the NSA are a flagrant (clear, obvious) violation of the 4th Amendment. to break the rules If you break traffic rules in Toronto, the fines are high. to break (down) the barriers Learning multiple languages breaks down barriers between peoples and cultures to break (up) a relationship "Honey, it's not you, it's me..." to break (up) a fight The police were called to break up the fighting between the drunk football fans The best way to learn these is a printed collocations dictionary like this one http://www.amazon.com/Longman-Collocations-Dictionary-Thesaurus-Online/dp/1408252260 (maybe at your university library???) I haven't found an online dictionary / database that is really user-friendly. You can use corpus databases to research collocations but they're not user-friendly. This site gives you basic collocations for most verbs: http://www.ozdic.com/collocation-dictionary/violate Working with how verbs are used i.e. collocations (rather than "What do they mean?") is a way to traverse that "intermediate plateau" ...

1) "breach" usually refers to a barrier of some sort, such as a wall. e.g. "Sir, the wall has been breached by the enemy. Should we fall back now??" 2) "break" is the most commonly used of the above four words, and can be used in almost any context 3) "violate" usually refers to a law or right, such as "that country violates it's peoples' human rights" or a person's integrity ("violate" in that context is often synonymous with rape") 4) "defy" usually refers to a regime, or some kind of other person or institution, it usually infers willful action against another person's wishes