密 - secrecy, density (pop), minuteness

poaching

smuggling oneself into a country; illegal immigration

crowding together; clustering together; close formation; swarm

density

fine (grain, workmanship, etc.); close (weave); delicate; intricate; elaborate

strict; close; precise; scrupulous

overcrowding; congestion; overpopulation

close (relationship, connection, etc.); intimate; near

rigour; rigor; closeness; compactness; tightly knit

close adhesion; sticking firmly (to); being glued (to)

secrecy; highly classified information

secret; private; surreptitious