go off at a tangent

Related to go off at a tangent: tangentially

go off at a tangent

To begin addressing or discussing a topic or topics not relevant to the main discussion. I tried to address the customer's problem, but she kept going off at a tangent and I couldn't understand what her true complaint was. In the middle of our conversation about my finances, my advisor went off at a tangent about current events.
See also: go, off, tangent
Farlex Dictionary of Idioms.

go/fly off at a ˈtangent

(British English) (American English go off on a ˈtangent) change suddenly from talking or thinking about one thing to talking or thinking about another: One moment the professor is working hard on a problem in physics, the next he’s gone off at a tangent and he’s talking about bees.
A tangent is a straight line that touches the outside of a curve but does not cross it.
See also: fly, go, off, tangent
Farlex Partner Idioms Dictionary
See also:
  • go (off) on a tangent
  • go off on a tangent
  • go/fly off at a tangent
  • fly off at a tangent
  • tangent
  • (off) on a tangent
  • on a tangent
  • sidetrack
  • (off) on a sidetrack
  • off on a sidetrack