Uncertainty, hazard, chance or risk, ambiguity and uncertainty in transactions. Technically, the sale of something which is not present at hand; or the sale of something where the consequences or outcome is not known. It can also be a sale involving risk or hazard in which one does not know whether it will come to be or not, such as fish in water or a bird in the air; or an event where assurance or non-assurance is subject to chance and thus not known to parties of a transaction. Can also mean uncertainty or a hazard that is likely to lead to a dispute in a contract.