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 un·der·staffed, un·der·staff·ing, un·der·staffs
To supply with fewer employees than required: Management was careful not to understaff the agency.