If I had the power to destroy words the first two to go would be "believe" and "deserve"

the word "belief" can prevent your model of reality from evolving when faced with new evidence.

Instead of saying you believe in something you'd have to say "I'm testing the hypothesis that..."

And this would allow us to entertain contradictory ideas simultaneously.

Do some people deserve to be rich while others deserve to be poor? Who deserves to be rewarded and who deserves to be punished? Only those already in power seem to control these decisions. As a result, too much evil can be done with the word "deserve."

A fun idea for a novel would be that a character has the ability to destroy words in their reality and each word they do this with can't be used for the remainder of the novel. Watch the cultural consequences of each disappearance.