The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
transitive verb o·ver·staffed, o·ver·staff·ing, o·ver·staffs
To supply with too many employees: Management was careful not to overstaff the agency.