In German an idiom is called a ‘Spracheigentuemlichkeit’, which means a peculiarity of a language. This is exactly what an idiom is. It is a conventionalized expression which usually means something very different from its literal meaning and is used by native speakers of the language all the time.
It is true that idioms may contradict some of the most basic grammar rules and often make no sense when interpreted literally. But in some cases it is possible to guess the meaning by seeing the usage , for example when someone says that he is ‘at daggers drawn’ with his brother, it is easy to infer that they are not at the best of terms with each other and have strained relations. When someone says his ‘hands are full’, it can be inferred that he cannot hold on to anything else. In a more metamorphic way we can infer that he is in no position to take up more tasks and is very busy already. When someone ‘sits on the fence’, he is on neither side and this is indicative of how in a given situation he does not take sides but occupies a neutral middle position. There are many such idioms whose meanings can be inferred this way.
But there are some instances like, for example, when someone says that he ‘hit the roof’ it is difficult to infer what it means if you have not come across the idiom before. ‘To hit the roof’ means to get extremely angry. If someone says that he is ‘on the wagon’ you cannot imagine that the person means that he doesn’t drink alcohol. Usually, you can figure out the meanings of such idioms if you have read them or heard them before. Sometimes the meaning of these idioms can be inferred contextually.
And that’s exactly why there are quite a few idioms which have been given, along with sentences, so as to make the usage clear and to make it easier for you to comprehend their meaning. Many of the idioms which have been mentioned are quite simple and are often used in spoken English. Some of them are not used that often but nevertheless have interesting meanings. The best practice for idioms is usage in everyday language and it will be very useful for you if you incorporate them in your vocabulary. Since there are a countless number of idioms used in English, the list is by no means exhaustive but it should help you in getting the general hang of understanding idioms.
All the very best,
Batch of 2015,
NALSAR University of Law.