ratting (Noun) — To furnish incriminating evidence to an officer of the law (usually in return for favours).
ratting (Verb) — Desert one's party or group of friends, for example, for one's personal advantage.
ratting (Verb) — (industry) employ scabs or strike breakers in.
ratting (Verb) — Take the place of work of someone on strike.
ratting (Verb) — Give (hair) the appearance of being fuller by using a rat.
ratting (Verb) — Catch rats, especially with dogs.
ratting (Verb) — Give away information about somebody.