Synonyms

      "A synonym means one of two or more words or expressions of the same language that have the same or nearly the same essential meaning in some or all senses".  -- Webster.
    However, in English no two words have exactly the same meaning and usage. Examples given below will show the distinction of some words which seem identical in meaning.

   Able normally means ability of someone or something. He is an able man.
   Capable means a particular ability to do something. He is capable of lifting one hundred kilograms.

   Arab means people of the Arab nation. He is an Arab Sheikh.
   Arabian represents something that is somehow related to Arab. Arabian deserts are extremely hot.
   Arabic means related to Arabian language or literature.

   Astonished is used when we want to express something that is above or beyond our comprehension. His feats of strength astonished us.
   Surprised is used when we say about something unexpected. We are surprised by his failure in the match.

   An artist is one skilled in one of the fine arts, as poetry, painting, sculpture, etc.
   An artisan is one skilled in the mechanic arts, as carpentry.
   An artiste is a professional singer, dancer etc. and it may represents both male and female.

   Authentic means the given details of something is true. His report gives an authentic account of the trouble.
   Genuine means the fact that something exist or happened truly. This is a genuine work of Mr. Hawkins.

   Avenge is used to express the responsibility of punishment to those who harm others or some particular persons. The man avenged the murder of his brother.
   Revenge means to punish people on his own who harm him. He taught him a good lesson for insulting him.

   An aeroplane is a sky flyer machine which weights much more than air. The aeroplane was crashed.
   An airship is a artificial sky flyer that is lighter than the air.
  
   Avocation is a subsidiary occupation, chiefly for pleasure.
   Vocation is a regular habitual or professional occupation. His vocation is law, but his avocation is gardening.

   A man is banished when he is compelled by a government to leave a country whether he is a native or foreigner. He was banished from the country.
   Exile is used when a man lives away from his native place. He lives as an exile from his native country.

   Battle is used to talk about a single and short fight. The battle of Palassey was fought by the fighters.
   War represents a much greater fight that consists of many battles. The Second World War was fought by a lot of soldiers.

   Big and large generally refer to size to quantity.
   Great refers to linear dimension or extent and is generally used with words denoting distance, height, length, etc.
A large field has a great length. A large or big some of money.
  
   Bring differs from fetch as fetch means, to go and bring. He brought some fruits. Fetch me the math book from the library.

   Bill represents the rule or law before its official release in the public, and after the review of the law when it is published officially, it's then called as an act.

** There are a lot more synonyms like these a few more will be published later.