Phrasal Verbs with 'Rat'

Rat on

Inform authorities about someone's wrongdoings

Example: She RATTED ON her neighbours to the police because they were smuggling alcohol from France.

Rat on

Fail to keep a promise

Example: He always RATS ON his promises.

Rat out

Inform the authorities about someone

Example: He RATTED me OUT to the police.

Rat through

Look for something hurriedly

Example: I RATTED THROUGH the papers on my desk but couldn't find the letter.