When we speak metaphorically, we use words in a non-literal sense. For example, when we say a writer casts light on a situation, we mean that the writer helps us understand it more clearly, in the same way that putting a light on in a dark room helps us see more clearly.
A-Metaphors based on the body
B-Metaphors based on weight Heavy can be used to mean serious or diff icult, as in heavy responsibility. A heavy burden can be either something heavy to carry or a diff icult responsibility to deal with, while a heavy book can be either one that weighs a lot or one with diff icult content. A weighty tome, however, would only be used to mean a book with difficult content. Similarly in weighty matters or weighty problems, weighty means diff icult and serious. Light, the opposite of heavy, can also be used metaphorically to mean carefree or lacking in seriousness. So light reading is reading material that is not serious. If you do something with a light heart, you feel carefree and happy. If someone has a slim chance of doing something, there is a chance, but it is small. Fat chance (very informal) means almost no chance.
C-Metaphors based on movement James did a lot of partying in his final year and ran into diff iculties with his course. His father was hopping mad (1) when he only just managed to get his degree. However, when he left university he walked straight into a job (2) in an excellent company. Some people jumped to the conclusion that this was because he’d started going out with the managing director’s daughter. His mother worried that, if their relationship hit the rocks (3), he would run into trouble at work too. 1 (informal) extremely angry 3 ended (metaphor based on a boat being destroyed on rocks) 2 got a job very easily
-English Collocations in Use, Advanced