Русско-англо-русский юридический словарь

mitigating circumstance Accompanying or accessory condition, event, or fact that (though not constituting a justification or excuse of an offense) may be considered by the courts as reducing the degree of culpability or liability of the accused. Such circumstances may include family or personal situations, and may help in attracting a sentence less severe than a typical sentence for similar offenses. (BusinessDictionary.com)

An onerous contract (contrato oneroso) is a contract that will include an exchange of consideration (something of value or an exchange of obligations). On the other hand, in gratuitous contracts (contralto gratuity) one party will always carry a burden in favour of the other party (i.e., gift or free loan). (Introduction to Brazilian Law edited by Fabian Deffenti, Weber Oliveira Barrel)

In contract law, we can sort the rules into two sorts, "default rules" and "mandatory rules."

Here's an example. The Uniform Commercial Code (or UCC, the codified law of contract that applies to contracts between businesses as a matter of state law in the United States) creates a duty to act in good faith--this is a mandatory rule, because this duty cannot be disclaimed by a contractual provision. The UCC also includes an implied "warranty of merchantability," that attaches to contracts, but can be waived by agreement--this is a default rule.

Grasping this distinction is important for at least two reasons. First, unless you know whether a given rule of contract law is a default rule or a mandatory rule, you don't really know the law. And it isn't always clear whether a given rule is one or the other: the usual tipoff is language like, "unless the contract provides otherwise" or "absent an agreement to the contrary." (Legal Theory Lexicon 050: Default Rules and Completeness)

In contract law, we can sort the rules into two sorts, "default rules" and "mandatory rules."

Here's an example. The Uniform Commercial Code (or UCC, the codified law of contract that applies to contracts between businesses as a matter of state law in the United States) creates a duty to act in good faith--this is a mandatory rule, because this duty cannot be disclaimed by a contractual provision. The UCC also includes an implied "warranty of merchantability," that attaches to contracts, but can be waived by agreement--this is a default rule.

Grasping this distinction is important for at least two reasons. First, unless you know whether a given rule of contract law is a default rule or a mandatory rule, you don't really know the law. And it isn't always clear whether a given rule is one or the other: the usual tipoff is language like, "unless the contract provides otherwise" or "absent an agreement to the contrary." (Legal Theory Lexicon 050: Default Rules and Completeness)