1 tell-tale

2 informer (esp. to police)

3 whistleblower

4 grass

1 secret code

2 ciphertext

3 password

4 PIN

1 secret

2 classifier: 个 gè

1 intimate

2 close

1 to keep sth confidential

2 to maintain secrecy

1 inextricably linked (idiom)

2 inseparable

1 flowering autumn grass, fine net (idiom); fig. abundant and exacting punishments prescribed by law

1 close relation, no gap (idiom); intimate and nothing can come between