expression, godan verb (-su)
make absolutely sure there are no omissions
Formal, emphatic expression used in official or business contexts to stress thoroughness and the avoidance of any oversight.
報告書の提出にあたり、万遺漏無きを期した。
When submitting the report, we made absolutely sure there were no omissions.
万全を期す means 'to make every effort to be perfect/prepared,' focusing on overall perfection, while 万遺漏無きを期す specifically emphasizes the absence of any omissions or oversights.
A fixed Sino-Japanese expression combining 万 (ten thousand/all), 遺漏 (omission), 無き (classical negative of ある), and を期す (to expect/ensure). The exact historical derivation is uncertain, but it follows a pattern of formal compound phrases used in bureaucratic and business writing.