壁垒森严 bì lěi sēn yán

DEFINITIONS

  1. closely guarded
  2. strongly fortified
  3. sharply divided

CHARACTERS

壁 bì
HSK 5
partition wall; walls of a house
垒 lěi rampart, military wall
森 sēn
HSK 4
forest; luxuriant vegetation
严 yán
HSK 4
strict, rigorous, rigid; stern