sēn​yán

rigid

森严 (森嚴) sēn​yán
rigid adjective
stern and strictly enforced, especially regarding social hierarchy, rules, or order

The social hierarchy in ancient times was extremely strict and could not be transgressed.

tight adjective
strictly guarded and highly secure, typically referring to military or police presence

Due to the presence of important leaders, security at the venue is very tight.

Frequency

Movie subtitles
2.00 per million appears in 1% of films
Written text
1.17 per million

Sources

Definitions
CC-CEDICT