A more thorough explanation:

Miserabile depositum is a legal term that refers to a deposit or bailment made in an emergency situation, such as a shipwreck, fire, or insurrection. For example, if a person is on a sinking ship and they deposit their valuables with someone else for safekeeping, that would be considered a miserabile depositum.

Miserere is a Latin term that means "have mercy." It is the first phrase of the 51st psalm and was used to test a person claiming benefit of clergy. For example, if someone was accused of a crime and claimed to be a member of the clergy, they would be asked to recite the first few lines of the 51st psalm, including the phrase "miserere."

Misericordia is a legal term that has several meanings. It can refer to mercy, an arbitrary fine as a punishment, or an exemption from a fine. For example, if a judge decides to show misericordia and reduce a defendant's sentence due to extenuating circumstances, that would be an example of the term being used to refer to mercy.

Misericordia communis is a legal term that refers to a fine levied on a whole county. For example, if a county is found to be in violation of a law and is fined as a result, that would be an example of misericordia communis being used.