Explain what an Imprecatory Psalm is and what type of Psalm it is.?

To imprecate means 'to pray evil against' or 'to invoke a curse upon'. Therefore the Psalm requests a 'curse' on those who are enemies of God. These Psalms are 7-35-55-59-69-79-109-137 and 139. An example from an Imprecatory Psalm reads 'may they be blotted out of the Book of Life and not be listed with the righteous'