head off
US /hed ɔf/
UK /hed ɔf/

1.
拦截, 阻止, 抢先
to prevent someone or something from going in a particular direction by getting in front of them
:
•
The police managed to head off the protestors before they reached the embassy.
警方设法在示威者到达大使馆前拦截了他们。
•
We need to head off the cattle before they wander too far.
我们需要在牛群走得太远之前把它们赶回来。