trip up

trip up  {v.}
1. To make (someone) unsteady on the feet; cause to miss a step, stumble, or fall.
A root tripped Billy up while he was running in the woods, and he fell and hurt his ankle.
2. To cause (someone) to make a mistake.
The teacher asked tricky questions in the test to trip up students who were not alert.
Categories: hurt {v.}