Diligence (Scots Law): a process; execution.
The term has several usages in legal proceedings involving creditors and debtors:
- Diligence Against the Heritage - A writ of execution by which the creditor proceeds against the real estate of the debtor.
- Diligence Incident - a writ ordering witnesses and others having information to provide testimony and answer questions.
- Diligence to Examine Havers - A process to obtain information from those who have it (hence, "havers"), and who must bring records, etc. with them to be examined.
- Diligence Against the Person - A writ of execution, by which the creditor proceeds against the person of the debtor.
- Second Diligence - Second letters issued where the first have been disregarded (similar to a contempt of court citation).
- Summary Diligence - Diligence issued in a summary manner, like an execution of a warrant of attorney.
- Diligence Against Witnesses - Process to compel the attendance of witnesses.
The definition was taken from the source. 
- ^ Shumaker, Walter A.; George Foster Longsdorf (1922). The Cyclopedic Law Dictionary (Second Edition by James C. Cahill ed.). Chicago: Callaghan and Company.