Senses
严密/ 嚴密 rigorous
strictly controlled; well-organized; thorough and precise without any loopholes
严密/ 嚴密 strictly secret
confidential; kept very private
严密/ 嚴密 tight
closed up tightly with no gaps; sealed or watertight
严密/ 嚴密 to tighten
to make something more strict or rigorous, such as a rule, a system, or discipline