trip up - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Make or cause someone to make a mistake, as in The other finalist tripped up when he was asked to spell “trireme,” or They tripped him up with that difficult question. [Second half of 1700s]