imprest
An advance of funds, especially to a government service or employee.
Calling on Lacon at the Cabinet Office to deliver the Circus's monthly imprest account for his inspection, he had been astonished to see Sam emerging from his private office, joking easily with Lacon and Saul Enderby of the Foreign Office.
Where it comes from
Prefix form of prest, perhaps after Italian imprestare, or perhaps from a misunderstanding of the phrase in prest.
Adapted from the Wiktionary entry imprest (CC BY-SA 4.0).