What does "rat out" mean?

To inform authorities (about someone); to tell on (somebody).

What is a synonym for "rat out"?

Common synonyms include: clepe, snitch.

verb, slang

verb, slang ·Uncommon ·College level

Verb

1
To inform authorities (about someone); to tell on (somebody). derogatory, slang, transitive
"Don't you dare rat me out or I'll kill you!"

"Don't you dare rat me out or I'll kill you!"