Definition of be on about in English:

be on about

British informal Talk about tediously and at length: she’s always on about doing one’s duty
More example sentences
  • She was the only person on board who could always understand what he was on about.
  • He talked a lot about the virtues of tolerance and fair play, but nobody had a clue what he was on about.
  • Half of them texted me back wondering what on earth I was on about.
See parent entry: on

Definition of be on about in: