law: Indian Contract Act, 1872 
  17. "Fraud defined
  "Fraud" means and includes any of the following acts
  
  committed by a party to a contract, or with his connivance, or by his agents
  , with intent to deceive another party thereto or his agent, or to induce
  
  him to enter into the contract:
  (1) the suggestion as a fact, of that which is not true, by one
  
  who does not believe it to be true;
  (2) the active concealment of a fact by one having knowledge or
  
  belief of the fact;
  (3) a promise made without any intention of performing it;
  (4) any other act fitted to deceive;
  (5) any such act or omission as the law specially declares to be
  
  fraudulent.
   Explanation:   Mere silence as to facts likely to
  
  affect the willingness of a person to enter into a contract is not fraud,
  
  unless the circumstances of the case are such that, regard being had to them,
  
  it is the duty of the person keeping silence to speak, or unless his silence
  
  is, in itself, equivalent to speech.
   Illustrations 
  (a) A sells, by auction, to B, a horse which A knows to be
  
  unsound. A says nothing to B about the horse's unsoundness. This is not fraud
  
  in A.
  (b) B is A’s daughter and has just come of age. Here the
  
  relation between the parties would make it A's duty to tell B if the horse is
  
  unsound.
  (c) B says to A- "If you do not deny it, I shall assume
  
  that the horse is sound". A says nothing. Here, A's silence is equivalent
  
  to speech.
  (d) A and B, being traders, enter upon a contract, A has private
  
  information of a change in prices which would affect B's willingness to proceed
  
  with the contract. A is not bound to inform B.