To undermine literally means to dig a hole underneath something, making it likely to collapse. But we more often use the word to describe sabotage or the act of weakening someone else’s efforts.

Originally spelled with a ‘y’ instead of an ‘i’, undermine has Germanic roots and means “to weaken, hinder, or impair.” Accidentally undermine the foundation of a house by digging a tunnel to China beneath it and you might be forgiven. Undermine your teacher’s authority by speaking out of turn and throwing spitballs and odds are you’ll get in trouble.

To undermine my authority?

You… don’t you fucking ever… fucking ever, ever undermine me again in front of my fucking troops.

They’re trying to undermine everything we’ve achieved over the last nineteen years.

I will provide our intelligence and law enforcement agencies with the tools they need to track and take out the terrorists without undermining our constitution and our freedom.