be on about (something)

To speak about something tediously and at great length. Primarily heard in UK. He just kept rambling about literary metaphors and imagery. I didn't know what he was on about! She's always on about some new show she has started watching. That guy sent another letter to the editor? OK, what's he on about this time?

go on (and on) about (something)

To continue or speak for a tedious or exasperating length of time. My date kept going on and on about his charity work, never even asking what I do for a living. That film was so stupid, and it just went on and on about this annoying couple's doomed relationship. I try to get a word in, but Uncle Ed always goes on about the most nonsensical things.

keep (going) on about (something)

To speak about something tediously and at great length. Primarily heard in UK. He just kept going on about literary metaphors and imagery. I didn't know what he was talking about! She always keeps on about some new show she has started watching.

keep (going) on about someone or something

to continue to talk excessively about someone or something. I wish you would not keep going on about Tom and Jill. Don't keep on about my haircut. It's perfect!

be on about

talk about tediously and at length. British informal

be ˈon about something

(informal) talk about something; mean something: I didn’t know what he was on about. It didn’t make sense.

be/go/keep ˈon about something

(informal, disapproving) keep talking about the same thing so that people become bored or annoyed: What’s she on about now? ♢ Don’t keep on about your terrible journey. It’s so boring.

be/go/keep on about something