(usually with “on” or “out”) To betray a person or party, especially by telling their secret to an authority or an enemy; to turn someone in.
He is going to rat us out!
To work as a scab, going against trade union policies.
(of a dog, etc.) To kill rats.
To scratch or score.
He ratted a vertical line on his face with a pocket knife.
To tear, rip, rend.
Ratted to shreds.
Damn, drat, blast; used in oaths.
Intoxicated