going off on one

Idiom (UK), see go off on one. To launch into a rant or lengthy discussion about some pet subject.

Might be derived from "going off on a tangent", but has more of a connotation of annoyance.

Sorry for going off on one, but I really feel strongly about this.

by Cedders March 13, 2011

go off on one

To be provoked by someone/something to such a point that a verbal reaction becomes inevitable.

Why's that kid shitting on Tom's car? Tom's gonna go off on one in a minute.

by Manson April 27, 2005