A synonym is a word that has the same (or almost the same) meaning as another word. It is very useful to have a good knowledge of synonyms. If you use the same words throughout your assignments, your writing will seem monotonous and unsophisticated.
For example, if you were writing an essay about the introduction of a government policy, your reader would find it rather boring if you kept using the words introduce, government and policy.
To make your writing more interesting, (where appropriate) you should use words that have the same or similar meanings. Here are some examples of words that you might use in the report about government policy.