understaffed

人手不足

We are understaffed and facing heavy workloads. 　／人手不足で仕事量が超過気味

XXX has been postponed due to understaffing at ABC.　／ABCで人手不足なのでXXXは延期します

My staff complain that we are understaffed.　／スタッフが人手不足だと不満を言っている