go off on a tangent
US /ɡoʊ ɔf ɑn ə ˈtæn.dʒənt/
UK /ɡoʊ ɔf ɑn ə ˈtæn.dʒənt/
1.
話が脱線する, 本題からそれる
to suddenly start talking or thinking about a different subject from the one you were originally discussing
:
•
The professor tends to go off on a tangent during his lectures, making them hard to follow.
教授は講義中に話が脱線する傾向があり、ついていくのが難しい。
•
We were discussing the budget, but then he suddenly went off on a tangent about his vacation plans.
予算について話し合っていたのに、彼は突然、休暇の計画について話が脱線した。