Gharar is the uncertainty in business. Gharar comes into play when anyone who is a party to the contract of business is not sure about the compensation he will get out of the contract, or the quantity or quality of compensation is not clear, or the time of delivery is not clear. To save oneself from gharar the contract of businesses should have explicit mention of every detail of the business.
The main types of Gharar are:
Gharar fi ajal: time of contract is not defined, uncertainaty of time.
Gharar fi miqdar: quantity is not defined, uncertainty of quantity.
Gharar fi sifah: quality is not defined, or specifications are not mentioned.